Early Paleozoic Brachiopods of the 

Moose River Synclinorium, Maine 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 

Early 

Moose 

Paleozoic Brachiopods of the 

River Synclinorium, Maine 

By ARTHUR J. BOUCOT 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 

Descriptions are jJrovided for large Early Devonian and 

Late Silurian brachiopod faunas of northwestern 

.1\llaine) together with small Early Silurian and 

Middle Ordovician faunas 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1973 
UNITED STATES DEPARTMENT OF THE INTERIOR 

ROGERS C. B. MORTON, Secretary 

GEOLOGICAL SURVEY 

V. E. McKelvey, Director 

Library of Congress catalog-card No. 73-600004 

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 

Price: $1.75, domestic postpaid; $1.50, GPO Bookstore Stock No. 2401-00325 
Abstract ----------------------------------------

Introduction -------------------------------------

Age of the faunas ------------------------------- Provinciality ________________ --- ___ --- __ -- ___ ----

Systematic paleontology --------------------------

Superfamily Orthacea ------------------------

Genus Orthostrophia Hall, 1883 ------------

Genus Orthambonites Pander, 1830 --------

Genus Dolerorthis Schuchert and Cooper, 

1931 ----------------------------------

Genus Ptychopleurella Schuchert and Cooper, 

1931 ----------------------------------

Genus Valc,ourea Raymond, 1911 ----------

Superfamily Dalmanellacea -------------------

Genus Resserella Bancroft, 1928 -----------

Genus Isorthis Kozlowski, 1929 ------------

Genus Levenea Schuchert and Cooper, 1931 _ 

Genus Dicaelosia King, 1850 ---------------

Genus Discomyorthis Johnson, 1970 --------

Genus Dalejina Havlicek, 1953 -------------

Genus Platyorthis Schuchert and Cooper, 

1931 ----------------------------------

Superfamily Enteletacea ----------------------

Genus Salopina Boucot, 1960 --------------

Superfamily Pentameracea --------------------

Genus Gypidula Hall, 1867 ----------------

Genus Sieberella Oehlert, 1887 -------------

Genus Pentamerus Sowerby, 1812 ----------

Superfamily Plectambonitacea -----------------

Genus Sowerbyites Teichert, 1937 ----------

Superfamily Strophomenacea ------------------

Genus Leptaena Dalman, 1828 -------------

Genus Stropheodonta Hall, 1852 -----------

Genus Leptostrophia Hall, 1892 ------------

Genus Protoleptostrophia Caster, 1939 _____ _ 

Genus Strophonella Hall, 1879 -------------

Superfamily Davidsoniacea --------------------

Genus Sc,huchertella Girty, 1904 -----------

Genus Hipparionyx Vanuxem, 1842 _______ _ 

Genus Leptaenisca Beecher, 1890 -----------

Superfamily Chonetacea ----------------------

Genus Cyrtoniscus Boucot and Harper, 1968_ 

Genus Eccentricosta Berdan, 1963 ----------

Genus Dawsonelloides Boucot and Harper, 

1968 ---------------------------------- Genus Eodevonaria Breger, 1906 -----------

Genus Chonostrophiella Boucot and Amsden, 

1964 ---------------------------------- Superfamily Rhynchonellacea ------------------

Genus Cupularostrum Sartenaer, 1961 _____ _ 

CONTENTS 

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Systematic paleontology-Continued 

Genus Ancillotoechia Havlicek, 1959 --------

Genus Sphaerirhynchia Cooper and MuirVVood, 1951 ----------------------------

Genus Sulcatina Schmidt, 1964 ------------

Genus Costellirostra Cooper, 1942 ----------

Genus Eatonia Hall, 1857 -----------------

Genus Machaeraria Cooper, 1955 -----------

Superfamily Atrypacea -----------------------

Genus Atrypa Dalman, 1828 ---------------

Genus Lissatrypa Twenhofel, 1914 ---------

Genus Nanospira Amsden, 1951 ------------

Superfamily Dayiacea ------------------------

Genus Leptoceolia Hall, 1859 --------------

Genus Coelospira Hall, 1863 ---------------

Superfamily Delthyridacea --------------------

Genus Hedeina, Boucot, 1957 --------------

Genus Delthyris Dalman, 1828 -------------

Genus Howellella Kozlowski, 1946 ----------

Genus Acrospirifer Helmbrecht and Wedekind, 1923 ----------------------------- Genus Antispirifer VVilliams and Breger, 

1916 ----------------------------------

Genus Costellispirifer Boucot, n. gen. -------

Genus Mucrospirifer Grabau, 1931 ---------

Genus Costispirifer Cooper, 1942 -----------

Genus Kozlowskiellina Boucot, 1958 --------

Genus Metaplasia Hall and Clarke, 1893 ___ _ 

Genus Plicoplasia Boucot, 1959 -------------

Superfamily Cyrtinacea ----------------------

Genus Cyrtina Davidson, 1858 -------------

Superfamily Athyridacea ---------------------

Genus Merista Suess, 1851 ----------------

Genus Meristella Hall, 1860 ---------------

Genus Charionoides Boucot, Johnson, and 

Staton, 1964 ---------------------------

Genus Nucleospira Hall, 1859 --------------

Genus Protathyris Kozlowski, 1929 --------

Superfamily Terebratulacea -------------------

Genus Nanothyris Cloud, 1942 -------------

Genus Rensselaeria Hall, 1859 -------------

Genus Beachia Hall and Clarke, 1893 ------

Genus Cloudothyris Boucot and Johnson, 

1968 ----------------------------------

Genus Amphigenia Hall, 1867 --------------

Genus Globithyris Cloud, 1942 -------------

Genus Mutationella Kozlowski, 1929 --------

References cited ----------------------------------

Index -------------------------------------------

III 

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IV 

PLATE 

FIGURES 

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3. 

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23. 

1-10. 

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15-19. 

20. 

21-25. 

CONTENTS 

ILLUSTRATIONS 

[Plates follow index] 

Orthostrophia, Schiz·oramma, Orthambonites?, and Dolerorthis. 

Dolerorthis, Dolerorthis?, Ptychopleurella, Valcourea, Resserella, and I sorthis. 

I sorthis, Levenea, unidentified orthoid, Dic,aelosia, and Discomyorthis. 

Discomyorthis, Dalejina, and Platyorthis. 

Salopina and Gypidula. 

Gypidula, Sieberella, Pentameru.s?, Sowerbyites?, Leptaena, and Stropheodonta. 

Leptostrophia, Leptostrophia?, and Protoleptostrophia. 

Protoleptostrophia and Strophonella. 

"Schuchertella," Hipparionyx, Leptaenisca, and Cyrtoniscus. 

Eccentricosta and Dawsonelloides. 

Dawsonelloides, Eodevona1·ia, and Chonostrophiella. 

Chonostrophiella, Cupularostrum, Cupularostrum?, Ancillotoechia, "Ancillotoechia," and Sphaerirhynchia. 

Sphaerirhynchia, Sphaerirhynchia?, and Sulcatina. 

Costellirostra, Eatonia, Mac.haeraria, and Atrypa. 

Atrypa, Lissatrypa, Nanospira?, Leptocoelia, Coelospira, and Hedeina. 

Delthyris, Howellella?, "Howellella," and Acrospirifer. 

Acrospirifer. 

Acrospirifer, Antispirifer, Costellispirifer, "Mucrospirifer," and Costispirifer. 

Megakozlowskiella, Metaplasia, Plicoplasia, and Cyrtina?. 

Merista, Meristella, Charionoides, Nucleospira, and Protathyris. 

Nanothyris, Rensselaeria, and Beachia. 

Beachia, Cloudothyris, and Amphigenia. 

Globithyris and Mutationella. 

Scattergrams for measurements of: 

1. Dolerorthis hobbstownensis _____________ -- _ ---- _ --------------------------------------

2. Ptychopleurella sp --------------------------------------------------------------------

3. Valcourea sp ------------------------------------------------------------------------

4. Discomyorthis musculosa solaris -------------------------------------------------------

5. Platyorthis planoconvexa ------------------------------------------------------------- 6. Salopina hitchcocki _________________________________ - __ -- _ -----------------------------

7. Cyrtoniscus nectus ------------------------------------------------------------------- 8. Dawsonelloides canadensis ________________ --------------------------------------------

9. Eodevonaria arcuata _______________________________ ----------------------------------

10. C honostrophiella complanata _______________________ ----------------------------------· 

Serial sections of Ancillotoechia haraganensis from the Haragan Shale of Oklahoma ------------· 

Serial s-tctions of Diabolirhynchia acinus from the Waldron Shale of Indiana ------------------· 

Serial sections of "Rhynchonella" bidentata from Silurian rocks near Klinteham, Gotland, Sweden -· 

Serial sections of "Ancillotoechia" cf. "A." altisulcata -----------------------------------------· 

Scattergrams for measurements of: 

15. "H owellella" tomheganensis ____________________________________ -- _________ -----------· 

16. Acrospirifer murchisoni -------------------------------------------------------------· 17. Acrospirifer atlanticus __________ ---- ________________ --- _______ --- _____________ -- __ --· 

18. Antispirifer harroldi ----------------------------------------------------------------· 19. Costellispirifer perimele _________________________________________ ----- _______________ -· 

Serial sections of Protathyris sp ___________________________________________________________ --· 

Scattergrams for measurements of: 

21. N anothyris hodgei _______________________________________________________________ ---· 

22. Amphigenia parva ------------------------------------------------------------------· 23. Globithyris call ida __________________________________________________________________ -· 

24. Globithyris diania -------------------------------------------------------------------· 25. Mutationella parlinensis _________________________________________________________ ----· 

TABLE 

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TABLE 1. Rib branching pattern for brachial valves of Dolerorthis hobbstownensis Boucot, n. SP------------------· 6 
EARLY PALEOZOIC BRACHIOPODS 

OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

By ARTHUR J. BoucoT 

ABSTRACT 

Brachiopods of the Moose River synclinorium of Maine 

are described from beds of Middle Ordovician, Early Silurian, 

Late Silurian, and Early Devonian ag·e, with emphasis on 

the Early Devonian brachiopods because of their relative 

abundance and because of their distribution in several zones 

and several marine communities. 

New genus Costellispirifer, a multiribbed delthyrid, is 

defined. New species are Dolerorthis hobbstowensis, Sieberella 

beckensis, Cupularostrum macrocosta, Machaeraria mainensis, 

"Howellella" tomheganensis, and Nanothyris hodgei. 

INTRODUCTION 

The stratigraphic and structural geology of the 

Moose River synclinorium has been dealt with 

earlier by Boucot (1961, 1969). Oliver (1960) described the Devonian corals and Stumm (1962) the 

Silurian corals; Boucot and Yochelson (1966) described the gastropods ; and Whittington and Campbell (1967) described some of the 8ilurian trilobites. 

E1arlier work on the faunas, chie,fly brachiopods, includes the studies of Clarke (1907, 1909), Schuchert 

(in Pifis,son and Schuchert, 1914), Williams and 

Breger (1916, in their report on the Chapman Sandsrtone fauna), and Goldring (1933). Miscellaneous 

reports by Boucot and others have dealt with particular parts of the brachiopod fauna in connection 

with various biologic studies: (Boucot, 1959a, deals 

with species of Metaplasia and Plicoplasia; Boucot 

and· others, 1963, deal with species of Mutationella; 

Boucot and Amsden, 1964, deal with species of 

Chonostrophiella; Boucot and Johnson, 1967a, deal 

with occurrences of Coelospira; and Boucot and 

Harper, 1968, deal with occurrences of Dawsonelloides, Cyrtoniscus, and Eodevonaria). Walmsley, 

Boucot, and Harper (1969) deal with Salopina from 

the Moose River synclinorium. 

The original purpose of the paleontologic and geologic work in the Moose River synclinorium was to 

determine if the undifferent,iated Early Devonian 

fauna as described by Clarke (1907, 1909) and Williams and Breger (1916) contained more than one 

horizon. Based on his own thesis studies (Cloud, 

1942) and an extensive field trip in the area in 1943, 

Preston E. Cloud, Jr. had suspected that more than 

one horizon was present and suggested the problem 

to Boucot in 1948 as a promis~ing subject for a dissertation. The purpose of this report is to document 

the brachiopod fauna. Extensive work on App~alachian province Early Devonian brachiopod fauna;s 

since the completion of the Moose River s~tudies in 

early 1956 has made possible effective comparison of 

them with similar faunas occurring elsewhere in the 

eastern half of North America. 

The locality numbers used in this report are from 

the U.S. Geological Survey's locality registers. Those 

with the suffix "SD" are from the Silurian-Devonian 

catalog, those with "CO" from the Cambrian-Ordovician catalog ._))etails of USGS locs. 2690-SD to 

4017-SD are given in Boucot (1969, appendix 1, p. 

105-117) and of USGS locs. 4841-SD, 4843-SD, 

5583-SD, 5586--SD, 5587-SD, and 5995-SD are 

given in Albee and Boudette (1972). U.S. National 

Museum brachiopod catalog numbers are assigned 

to all the illustrated, figured, and measured 

specimens. 

Boucot and Heath (Boucot, 1969) summarize the 

geology of the Moose River and Roach River synclinoria, including the structure, stratigraphy, fossil 

localities, and animal communities. Plate 30 of that 

report is a generalized geologic map on which the 

fossil localities ar·e shown. Stratigraphic nomenclature corresponds with that used in the descriptive 

part of this report. 

AGE OF THE FAUNAS 

Early Paleozoic faunas of Middle Ordovician, 

E-arly Silurian, Late Silurian, and Early Devonian 

age are associated within the Moose River synclinorium. The Middle Ordovician fauna, which includes the brachiopods Orthambonites? sp., Valcourea sp., and Sowerbyites? sp., was previously 

concluded to be of early to middle Middle Ordovician 

age as evidenced by the braohiopods. 

Early Silurian fossHs are not known in the Moose 

River synclinorium proper, but have been recorded 

at Limestone Hill in the Stratton quadrangle, which 

lies on the southeastern side of the synclinorium 

(Boucot, 1969). On Limestone Hill the occurrence of 

Pentamerus? sp., Dicaelosia s.p., and a species of 

Amphistrophia similar to A. funiculata suggests a 

late larte Llandovery or possibly very early Wenlock 

age, fro·m the occurrence of Dicaelosia (late Llandovery-Wenlock type) as well as Arnphistrophia 

1 
2 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

similar to A. funiculata. The occurrence of Atrypa 

"reticularis," Howellella, and Eospirifer precludes 

the possibility of thes·e being of pre-late Llandovery 

age, as these genera are unknown els.ewhere in the 

world earlier than the late Llandovery. 

The Late Silurian faunas are from four sources: 

Lobs:t€~r Lake Formation, USGS loc. 3488-SD of the 

Hardwood Mountain Formation, the remainder of 

the Hardwood Mountain Formation, and lower conglomerate member of the Hobbstown Formation. 

Brachiopods are very rare in the Lobster Lake 

Formation and were not studied in connection with 

this report. They include uncollected, poorly p·reserved specimens of Kirkidium cf. K. knighti from 

the southwe1st shore of Lobster Lake, and a Gypidulx 

similar to the one present in the Hardwood Mountain 

Formation from the northeas1t shore (USNM loc. 

12113). Stumm (1962, p. 2, 3, 4, 6) and Oliver (1962, 

p. 11) both consider that the oorals of the Lobs·ter 

Lake Formation are similar to ·those of the Ludlow 

and Pridoli age Hardwood Mountain and Mont Wi8-

sick Formations. The evidence from both the brachiopods and corals is oons:isrtent with a Ludlow a.ge, but 

a Pridoli age cannot be ruled out, at least in pwrt. 

Thi:s conclusion also applies for at least parts of 

both the Hardwood Mountain and Mont Wis1soick 

Formations. In view of the probable Pridoli age of 

part of the Hardwood Mountain, a Pridoli age, at 

least in part, for any "Ludlow" age unit in northern 

Maine must be considered likely, unless oompelling 

evidence to the contrary is available. 

USGS loc. 3488-SD has been a~Ssigned to the Hardwood Mountain Formation, which repre:s•enrts a 

single exposure of calcareous siltsrtone in an area. adjacent to extensive e•xposures o.f a lithologically s·imilar unit. However, the fauna of the loca.Hrty is comple:tely different from that found els1ewhere in the 

Hardwood Mountain. Inspection of table· 8 in Boucot 

(1969) shows that among the 13 brachiopod taxa 

reco·gniz.ed at this locality only thre·e have been 

recognized els·e·where in the formation, and these 

three are the ubiquitous forms, Atrypa "reticularis," 

Lissatrypa, and Coelospira. The locality has a lower 

age limit of late Wenlock, as shown by the presence 

among the brachiopods of Coelospira and Sulcatina. 

The ostracodes and bry.ozoans (fene3:tellids are abundant) are rela:tive~ly undiagnos:tic or are new. Whittington and Campbell (1967) conclude that the 

trilobite fauna from USGS loc. 3488-SD may be of 

late Wenlock or early Ludlow age. Structurally the 

locality is inferred to be near the base of the Hardwood Mountain Formation. Summing up all of these 

data, the author assigns at this tim·e an inferred late 

Wenlock or Ludlow age for the locality. 

The Hardwood Mountain Formation as presently 

mapped (1969) consists of three dis·continuous 

areas; The Spencer Mountain outlier and adjacent 

southwest prong of the Moos·e River synclinorium, 

the area to the north of Little Big Wood Pond, and 

a few exposures on the eastern flank of Sally Mountain. The exposures in both the Sally Mountain and 

Little Big Wood Pond areas have yielded Eccentricosta, a genus restricted in the central Appalachians 

to beds of Pridoli age. Unfortunately Eccentricosta 

is virually unknown from an evolutionary point of 

view and is difficult to use in determining the age of 

the containing beds in the northern Appalachians. 

The occurrence (Klapper in Boucot, 1969) of very 

latest Ludlow through Pridoli age conodonts at one 

locality on the north shore of Little Big Wood Pond 

makes it likely that the northern exposures of the 

formation which contain Eccentricosta are indeed of 

Pridoli age. Corals from the Little Big Wood Pond 

area were concluded by both Stumm (1962) and 

Oliver (1962), to be of "Ludlow" age, but this age 

determination is an earlier one made when the distinction between strata of Ludlow and Pridoli age 

was not yet practicable within the northern Appalachians. J. M. Berdan, in Boucot (1969) considers 

that ostracodes from the Hardwood Mountain Formation of the Little Big Wood Pond area can be best 

correlated with the Pridoli age Tonoloway Limestone. Considering all this evidence and the fact that 

the conodont collection was made within about ten 

feet of the unit's base, the author concludes that the 

Hardwood Mountain Formation of the Sally Mountain and Little Big Wood Pond area is largely, if not 

entirely, of Pridoli age. 

The Hardwood Mountain Formation of the Spencer Mountain outlier and of the adjacent synclinorium to the southeast does not contain any brachiopods of zonal value, but the ostracodes (see Berdan 

in Boucot, 1969) do indicate a correlation with the 

Pridoli age Tonoloway Limestone. The overlying 

fauna recovered from the basal few inches of the 

Hobbstown Formation is certainly Silurian, as 

shown by the presence in the Appalachians of such 

brachiopod genera as Dolerorthis, Ptychopleurella, 

Resserella, and Delthyris (Delthyris). The ostracode Limbinaria? cf. L.? muricata (Berdan in Boucot, 1969) suggests a Tonoloway, that is, Pridoli correlation. The available evidence suggests that the 

Hardwood Mountain Formation of the Spencer 

Mountain outlier and adjacent synclinorium is at 

least partly, if not almost entirely of Pridoli age, but 

a Ludlow or even a late Wen lock age for a part of 

the formation seems reasonable at this time. 

The fauna obtained from the basal few inches of 
PROVINCIALITY 3 

the Hobbstown Formation's lower conglomerate 

m·ember is considered to be of probable Pridoli age. 

Other considerations (Boucot, 1969) make it likely 

that this fauna from the basal few inches was reworked from Silurian sediment and redeposited in 

an essentially Lower Devonian rock unit. 

The Lower Devonian faunas of the Moose River 

synclinorium may be divided into three age units: a 

lower unit of middle or late Helderberg age (s·ee Boucot and Johnson, 1967b), a middle unit of Oriskany 

age, and an upper unit of Schoharie age. Strata of 

Esopus age that contain recognizable marine fossils 

have not been found in this region. 

Strata of middle or late Helderberg age containing 

datable fossils include the basal Seboomook Formation near Beck Pond, the Bear Pond Limestone Member of the Seboomook Formation, the Beck Pond 

Limestone, and the Parker Bog Formation. Boucot 

and Johnson ( 1967b) have summarized the arguments for the middle or late Helderberg age of the 

Beck Pond Limestone and the Bear Pond Limestone 

Member of the Seboomook. The scanty fauna from 

the Parker Bog Formation is consistent with a 

middle or late Helderberg age but cannot be used to 

prove it. Similarly scanty are the basal Seboomook 

fossils of Helderberg age in the Beck Pond area 

(these shells occur in a stratigraphic position below 

the Bear Pond Limes·tone Member) , although the 

occurrence of Spinoplasia would appear to rule out 

an early Helderberg age. 

Strata of Oriskany age within the synclinorium 

include the Tarratine Formation and most of the 

Seboomook Formation. The presence of Rensselaeria, 

Hipparionyx, Beachia, Costispirifer, and Daws·onelloides is consistent with an Oriskany age for the 

Tarratine Formation. The intertonguing relations of 

the Seboomook and the Tarra~tine (Boucot, 1969) 

and the similarity of the fauna indicate that the 

greater part of the Seboomook is of Oriskany age in 

this region. 

The Schoharie age beds in the Moose River synclinorium include the Tomhegan Formation and the 

Kineo Rhyolite. Only the Tomhegan has yielded diagnostic fossils. The presence of small Amphigenia, 

Eodevonaria arcuata, Acrospirifer atlanticus, and 

Charionoides doris indicate that the Tomheg1a.n fauna 

is of Schoharie age. 

PROVINCIALITY 

The Middle Ordovician Kennebec Formation has 

yielded a very small fauna (Boucot, 1969), but all 

the elements present suggest an association with 

Central and Southern Appalachian rather than with 

northern European forms. Other shelly faunas from 

northern Maine of Ordovician age (Neuman, 1968) 

differ sharply from that of the Kennebec Formation. 

This evidence indicates that Maine was a boundary 

region during the Ordovician and included European-type faunas in both Aroostook and Penobscot 

Counties to the northeast and Appalachian types in 

Somerset County to the southwest. The evidence obtained by Lesperance (1968) for the Late Ordovician 

trilobites of Gaspe is similar in that it indicates that 

Gaspe lay near a boundary between Appalachianand European-type regions for at least part of the 

Ordovician. 

The Silurian (see Boucot and others, 1969) was a 

time of great cosmopolitanism for the brachiopod 

faunas. Toward the end of the Silurian this situation began to deteriorate into a more provincial condition. In Somerset County, the presence of the 

endemic Appalachian chonetid genus E ccentricosta 

is consistent with this conclusion, as the containing 

beds are probably of Pridoli, that is, latest Silurian 

age. The ostracode fauna of the central Appalachians 

differs largely from that of northern Europe, and the 

occurrence of central Appalachian-type ostracodes in 

the probably Pridoli-age strata of Somerset County 

is in great contrast to the Baltic-type fauna of coastal Maine (Berdan, p. 39, 40 and Martinsson, p. 41-

43, in Berry and Boucot, 1970). These data indicate 

that during Pridoli time there was a boundary between an Old World province-type fauna in coastal 

Maine and adj aeent New Brunswick, and the Appalachian province precursors in northern Maine, adjacent Quebec and through Gaspe. It is emphasized, 

however, that during Pridoli time most of the brachiopods of northern Maine, adjacent Quebec, and 

Gaspe belonged to relatively cosmopolitan genera. 

The scanty pre-Pridoli age Silurian fauna in this 

region from Lim·estone Hill is concluded to be of 

late late Llandovery age and is a typical Silurian 

cosmopolitan shelly fauna. 

The Helderberg faunas of the Moose River synclinorium contain a variety of brachiopods, all of which 

have Appalachian province affinities or belong to 

widespread taxa. The same situation holds for 

faunas of Oriskany and Schoharie age. The only 

anomaly is the abundance of Mutationella in the 

Oriskany age faunas, because this genus, which also 

occurs in the Rhenish community of the Old World 

province, can be interpreted to be an Old World 

genus, but more probably it is a member of a relatively near-shore community (the "Mutationella 

community" of Boucot and Johnson, 1967b) which 

also occurs in the Old World province. The same 

problem is posed by the abundant representatives of 

Globithy1-is which occur in the widespread globithy-
4 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

rid community of both Oriskany and Schoharie age 

in the Moose River synclinorium. 'fhe earliest representatives in this region of an undoubted Old World 

province brachiopod fauna occur about fifty miles 

to the northwest at Saint George, Quebec, whe:re 

several genera of Old World province affinity occur 

in the Onondaga (that is, Eifelian) age Famine 

Limestone. Oliver's(1967) analysis of the coral fauna 

in eastern North America during the Helderberg 

through Onondaga interval is similar to the brachiopod analysis presented here. 

SYSTEMATIC PALEONTOLOGY 

PHYLUM BRACHIOPODA 

Class ARTICULATA 

Suborder ORTHOIDEA 

Superfamily ORTHACEA 

Family ORTHIDAE 

Subfamily ORTHOSTROPHIINAE 

Genus ORTHOSTROPHIA Hall, 1883 

As pointed out by Williams (1951, p. 91), Orthostrophia is predominantly orthid in its general form. 

Williams emphasized the orthid nature of the cardinalia associa.ted with plectorthid-type pallial marks. 

Williams ( 1951, p. 90), after finding a dolerorthid 

(his Schizoramma cf. subplicata) with plectorthidtype pallial marks, concluded that pallial marks were 

of less value in making family a.ssignments than cardinalia. However, Williams, in reassigning Orthostrophia to the Hesperorthinae, ignored the external 

and internal differences between Orthostrophia and 

the genera of the Hesperorthinae which constitute 

valid grounds for leaving the former in a distinct 

subfamily, albeit of the Orthidae rather than the 

Plectorthidae. More recently Williams (1965) classified 01·thostrophia with the Orthinae. 

Probably the most prominent feature of Orthostrophia vis-a-vis the hesperorthinids is the presence 

in the former of a rev'ersal of fold and sulcus from 

the presence in the umbonal region of a pedicle valve 

fold to a prominent sulcus anteriorly and corresponding feartures in the brachial valve. Orthostrophia has accessory ridges p·arallelling the linear 

cardinal process in a manner reminiscent of true 

Schizoramma (pl. 1, figs. 13, 14). 

Orthostrophia cf. 0. brownsportensis Amsden, 1949 

Plate 1, figures 1-5 

Exterior.-Shells transverse in outline. Straight 

hinge line p·osition of maximum width. Lateral margins relatively straight, normal to hinge line posteriorly, round evenly into anterior margin. Anterior 

margin evenly rounded, crenulate, unisulcate. Pedicle valve bears low fold in umbonal region which 

becomes transformed into prominent sulcus anteriorly; brachial valve bears low sulcus in umbonal 

region which becomes transformed into fold anteriorly. Radial costellae increase by both bifurcation and im·plantation. Concentric filae, growth lines. 

Pedicle valve interarea strongly apsacline, about 

twice length anacline brachial valve interarea. Both 

valves evenly convex. Pedicle valve about twice as 

deep as brachial valve. 

Pedicle valve interior.-Dental lamellae very 

short, almost completely obsolescent. Hinge teeth 

stout. Muscle field very short, divided into median 

s~ector bounded laterally by two lateral sectors, all 

concentrically striated. Radial ornamentation impress prominent except in delthyrial cavity. At bottom of delthyrial cavity is low subcircular ridge 

which may have bounded adjustor attachment area. 

Brachial valve interior.-Cardinalia consist of 

stubby brachiophores bounding edge of notothyrial 

cavity, linear cardinal process, pair of thin ridges 

paralleling closely cardinal process margins. Low 

myophragm extends anteriorly from cardinal process margins. Low myophragm extends anteriorly 

from cardinal process ; bisects very deeply impressed 

adductor field. Adductor field quadripartite. 

Comparison.-0. cf. 0. brownsportensis is more 

finely costellate than 0. strophomenoides and bears 

a narrower fold and sulcus anteriorly. 

Occur1~ence.-USGS loc. 4843-SD, Attean quad-

~angle, Somerset County, Maine. 

Stra.tigraphic location.-Hardwood Mountain Formation (Upper Silurian). 

Figured specimens.-USNM 160109-160111. 

Orthostrophia cf. 0. strophomenoides (Hall, 1857) 

Plate 1, figures 6-12 

Exterior.-Shell gently biconvex, with pedicle 

valve possessing greater convexity. Outline subcircular, greatest width near midlength. Brachial valve 

sulcate posteriorly, bears fold anteriorly; pedicle 

valve lacks sulcus posteriorly, develops one anteriorly in large shells. Hinge line straight. Pedicle valve 

interarea about three times as long as that of brachial valve. Pedicle valve interarea apsacline, that of 

b~achial valve anacline. Both valves multicostellate; 

costellae appear to originate largely by bifurcation. 

Anterior commissure uniplicate, crenulate. 

Pedicle valve interior.-Interior prepared impression does not show interior details very satisfactorily. Short dental lamellae present; laterally bound 

muscle attachment area. Latter restricted to delthyrial cavity, appears tripartite, with median portion slightly more depressed than two lateral 

portions. Medial impression Expands anteriorly, 

probably adductors attachment site. Muscle field 
SYSTEMATIC PALEONTOLOGY 5 

crossed by striations subparallel to hinge line. No 

trace of pallial marks found on specimen studied. 

External costellae impression marked, particularly in antero-median part of shell ; this feature may 

be partly associated with deformation of the 

specimen. 

Brachial valve interior.-Anterior portion dental 

sockets formed by stubby brachiophores, posterior 

portion by interarea edge. Linear cardinal process 

grades anteriorly into short myophragm which has 

triangular cross section. Subcircular adductor attachment area divided medially by myophragm, 

bounded laterally by low ridges, divided transversely by low ridge normal to myophragm. Pallial markings not identified on available material. Impression 

of costellae on interior marked in anterior and 

lateral portions of shell. Valves large, several are 35 

to 40 mm wide. 

Comparison.-Material from the Beck Pond Limestone most closely resembles 0. strophomenoides 

from the New Scotland Formation of eastern New 

York, but poor preservation and inadequate number 

of specimens preclude positive specific identification. 

Occurrence.-USGS loc. 3499-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian). 

Distribution.-Species is known only from eastern 

North America and Oklahoma. 

Figured specimens.-USNM 125785B, 125786AB. 

Unfigured specimens.-USNM 125787 A, 125788B, 

125789C, 125790D, 125791E, 125792A. 

Subfamily ORTHINAE 

Genus ORTHAMBONITES Pander, 1830 

Ortbambonites? sp. 

Plate 1, figures 15-17 

Exterior.-Unequally biconvex shell, brachial 

valve gently convex, pedicle valve subpyramidal. 

Greatest width at straight hinge line. Pedicle valve 

interarea steeply apsacline, brachial valve interarea 

appears anacline. Pedicle valve interarea much 

longer than that of brachial valve. Lateral margins 

gently rounded. Anterior margin re.ctimarginate, 

crenulate. Radiating costae; no secondary costae 

evident on specimen studied. 

Comparison.-The single impression of the exterior available is questionably assigned to Orthambonites on the basis of convexity of the brachial 

valve which is unlike the flat brachial valve of Hesperorthis. Pedicle valve interarea is too poorly preserved for the determination of the presence or absence of a pseudodeltidium. 

Occurrence.-USGS loc. 4317-CO, Brassua Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Kennebec Formation 

(middle Middle Ordovician) . 

Figured specimen.-USNM 125753. 

Family HES PERORTHIDAE. 

Subfamify !DOLERORTHINAE 

Genus DOLERORTHIS Scbucbert and Cooper, 1931 

Dolerortbis bobbstownensis Boucot, n. sp. 

Plate 1, figures 18-26 

Exterior.-Shells unequally biconvex, pedicle 

valve subconical, brachial valve gently convex; elliptical to subcircular in outline. Brachial valve sulcus 

more prominent in early than in late growth stages. 

Hinge line straight, lateral margins rounded, greatest width occurring about midlength. Pedicle valve 

interarea steeply apsacline, in crushed specimens it 

appears gently apsacline ; brachial valve interarea 

gently anacline. Pedicle valve interarea about three 

times as long as that of brachial valve. Sides of delthyrium subparallel but in crushed specimens they 

commonly include angle of about 45°. Number of primary plications (table 1) originating near beak 

usually six or s·even each side of midline. Two secondary plications occur in brachial valve sulcus ; similarly on either side of pedicle valve medial primary 

plication. Secondary plications bifurcate a few millimeters anterior to umbo. Secondary plications associated with other primary plications originate 

slightly anterior to those in sulcus or associated with 

median primary of pedicle valve. Those originating 

on brachial valve do so on medial side of primary 

plication, whereas reverse true of pedicle valve. T1ertiary plications uncommon except in third primary 

which gives rise to tertiary plication in about 50 

percent of specimens examined. Interspaces crossed 

by prominent filae. Anterior commissure of small 

shells sulcate, but in larger specimens becomes almost rectimarginate, crenulate. 

Pedicle valve interior.-Short dental lamellae diverge laterally from anterior face of palintrope and 

bound muscle attachment area. Hinge teeth stubby 

and occur medially on hinge line; they are supported 

in part by dental lamellae. Muscle field located entirely within delthyrial cavity, lies on pad of secondary 

material which floors this part of valve and raises it 

slightly above level of rest of valve. Anterior margin 

crenulated, both anterior and lateral portions of 

shell bear impression of external coarse costellae. 

Brachial valve interior.-Cardinalia consist of 

linear, blade-like cardinal process resting on notothyrial platform bounded by short, stout brachiophores whose posterior faces are in same plane as 

interarea. Dental sockets floored by fulcra} plates, 
6 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

TABLE 1.-Rib branching pattern for brachial '/Jalves of Dolerorthis hobbstownensis Bouc.ot, n. sp 

[From collection of specimens numbered 1-55, from base of Hobbstown Formation, USGS loc. 3479-SD, Spencer Lake quadrangle, Somerset County, Maine 1, 2, 3 ... primary costella; 12 median ~>econdary costella; 1a tertiary to median secondary costella; 2a, 3a ... lateral secondary costella to respective primary. L and R refer to left and right sit;le of valve; 1 and 2 refer to one or more costellae of that order in that position] 

Speci- 1 12 1a 2 2a a 33 4 4a 6 5a 6 7 8 men L R L R L R L R L R L R L R L R L R L R L R L R L R L R 

1 - 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

5 - 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 

7 - 1 1 1 1 1 1 2 1 1 1 2 1 1 1 1 

9 - 1 1 1 1 1 1 1 1 1 1 1 2 2 1 1 1 1 1 1 1 

10 - 1 1 1 1 1 1 1 1 1 1 

11 - 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

22 - 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 

24 - 1 1 1 1 1 1 1 2 1 1 1 

25 - 1 1 1 1 1 1 1 1 2 1 1 

27 - 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

28 - 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

29 - 1 1 1 1 1 1 1 1 

30 - 1 1 1 1 1 1 1 1 1 1 1 2 2 1 1 1 1 1 1 1 1 

31 - 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 

39 - 1 1 1 1 1 1 1 1 1 1 1 1 1 

42 - 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

47 - 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

49 - 1 1 1 1 1 1 2 1 1 1 2 2 1 1 1 1 1 1 

50 - 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 

51 - 1 1 1 1 1 1 1 1 2 1 1 2 2 1 1 1 

54 - 1 1 1 1 1 1 1 1 1 1 1 

55 1 1 2 -- 1 2 1 --

laterally formed by outer face of brachiophores and 

by inner face of interarea. Low rounded median septum extends from anterior face of notothyrial platform to about midlength. Adductor impressions 

poorly impress·ed, but noticeable posteriorly, fading 

anteriorly. Anterior margin crenulated, and anterior 

and lateral portions of shell impressed by external 

costellae. 

M ea.surements .-Scatter diagrams of length versus width for both pedicle and brachial valves are 

essentially linear (fig. 1). The plot for pedicle valves 

exhibits greater degree of dispersion than that for 

brachial valves. This greater dispersion is probably 

due to the pedicle valve having been a far more convex valve which upon crushing (most of specimens 

are crushed) has had its linear dimensions ~subjected 

to a greater amount of alteration than the relatively 

flat brachial valve. The slope of both plots is about 

55 o It is unlikely that there is a radical change in 

slope of the growth curve from small specimens 

(smaller than available for study) to large specimens 

because the extrapolated growth line would approximately pass through the origin. A greater degree of 

dispersion accompanies increase in overall size, but 

this does not indicate a greater degree of variation 

but rather about the same percentage variation. Both 

samples are strongly skewed towards larger sizes 

Which suggests that abstraction of smaller specimens 

from sample occurred, although it is unclear whether 

this occurred during transportation or in situ. 

Comparison.-D. hobbstownensis is more coarsely 

cos. tellate than the p·reviously described species of 

rJ) 

a: 

w 

1-

w 

~ 

20~----------~------------~-----------. 

. . : · .... 

. ~· 

·. ·.· . 

10~-----------+---.-.--------4-----------~ 

Brachial valve 

j OL-----------~------------~----------~ 

~ 

z 

~ 20~----------~------------~----------~ 

:r: 

It!) 

z 

w 

..J . . . ,. . ·~· ~ ... :·· · . 

. . 10~----------~------------4-----------~ 

.. : 

Pedicle valve 

10 20 30 

WIDTH, IN Ml LLIMETERS 

FIGURE !.-Comparison of length versus width for brachial 

and pedicle valves of Dolerorthis hobbstownensis from 

the base of the Hobbstown Formation. Locality 3479-SD, 

Spencer Lake quadrangle, Somerset County, Maine. 
SYSTEMATIC PALEONTOLOGY 7 

Dolerorthis sensu stricto. The rib-branching pattern 

of D. hobbstownensis is less complica~ted than that 

of the previously described species. 

Occurrence.-USGS locs. 2712-SD, 3479-SD, 

Spencer Lake quadrangle, Some·rset County, Maine. 

Stratigraphic location.-Base of Hobbstown Formation (Upper Silurian). Possibly Late Silurian 

shells reworked in basal part of a Devonian unit 

(Boucot, 1969, p. 39-40). 

Figured specimens.-USNM 125796A, B (holotyp'e) , 125797B, 125903A. 

Measured paratypes.-USNM 125799. 

Unmeasured specimens.-USNM 126272, 126273. 

Dolerorthis cf. D. hami (Amsden, 1951) 

Plate 2, figures 1-5 

Exterior.-Shell unequally biconvex, pedicle valve 

subconical, brachial valve g'ently convex. Brachial 

valve sulcate. Shell outline subcircular to elliptical. 

Anterior commissure sulcate, crenulate. Straight 

hinge line, greates.t width near midlength. Pedicle 

valve interarea steeply apsacline, brachial valve interarea anacline. Costellae which increase by bifurcation. Brachial valve sulcus contains two pairs 

secondary cos.tellae, one pair tertiary costellae. Fine 

filar ornamentation concentrically crosses interspaces, absent from crests of costellae. 

Pedicle valve interior.-Short dental plates laterally bound low pad. secondary material in delthyrial 

cavity on which are situated impressions of musclre 

field. Hinge teeth nature not clear on one specimen 

available for study. External costellae impressions 

reflected on anterior and lateral portions of interior. 

Brachial valve interior.-Cardinalia consist of 

linear, bladelike cardinal process situated on notothyrial platform lateral to which are located relatively short anteriorly directed brachiophores. Muscle field nature difficult to ascertain on one specimen 

available but paired adductor impressions near anterior face notothyrial platform are medially divided by low myophragm. External costellae impression reflected on anterior and lateral portions of 

interior. 

Comparison.-The material from Maine is inadequate for definitely determining specific position; 

most closely resembles D. hami. 

Occurrence.-USGS loc. 3479-SD, Spencer Lake 

quadrangle; loc. 5995-SD, Attean quadrangle, Somerset County, Maine. 

Stratigraphic location.-Base of Hobbstown Formation and Hardwood Mountain Formation (Upper 

Silurian). 

Distribution.-Central Oklahoma; northern 

Maine. 

Figured specimens.-USNM 125794A-B, 

125795A-B, 160112. 

Dolerorthis? sp. 

Plate 2, figures 6-8 

Exterior.-Gently convex pedicle valve (no brachial valve available) has subcircular outline. Hinge 

line straight, greatest width a.t hinge line. Pedicle 

valve sulcate. Lateral extremities rounded towards 

anterior. Anterior commissure gently uniplicate, 

crenula.te. Numerous bifurcating costellae crossed 

by filae restricted to interspaces. 

Pedicle valve interior.-Hinge teeth located on 

medial margin of hinge line, appear short. Dental 

plates short, laterally bound muscle attachment area. 

Muscle field located on pad secondary material that 

raises delthyrial cavity floor slightly above rest of 

valve. Muscle field nature not elucidated from fragmentary specimen available. External costellae impression leaves imprint on anterior, lateral portions 

of shell. 

Comparison.-The two fragmentary specimens 

available are insufficient to assign material generically. Relatively fine costellae, nature of pedicle valve 

muscle field, presence of filae in interspaces between 

costellae are suggestive of Dolerorthis. Most closely 

resembles forms like D. rustica osiliensis (Schrenk, 

1858), unlike pauciplicate forms assigned to genus. 

Occurrence.-USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Base of Hobbstown Formation (Upper Silurian). 

Figured specimens.-USNM 125800B-C. 

Unfigured specimens.-USNM 125800A. 

Subfamily GL YPTORTHINAE 

Genus PTYCHOPLEURELLA Schuchert and Cooper, 1931 

Ptychopleurella sp. 

Plate 2, figures 9-17 

Exterior.-Unequally biconvex, pedicle valve subconical, brachial valve convex. Brachial valve bears 

deep median sulcus. Hinge line straight, maximum 

width slightly anterior of midlength. Shell outline 

transversely elliptical, width about one and one-half 

times length. Pedicle valve interarea apsacline, 

brachial valve interarea orthocline. Anterior commissure rectimarginate, crenulate. Delthyrium sides 

subparallel, apparently unmodified by delthyrial 

structures. Primary costellae bifurcate anteriorly 

giving rise to secondary and tertiary cos,tellae. Small 

specimens (less than a few millimeters long) do not 

possess secondary or tertiary costellae) . Three to 

four primary plications present either side midline. 

Coarse,· radial ornamentation crossed by fine, concentric lamellae. 
8 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

Pedicle valve interior.-Short dental plates laterally bound delthyrial cavity, intersect palintrope anterior face lateral to delthyrial margin. Hinge teeth 

short, located medial part hinge line. Secondary material pad laid down in d.elthyrial cavity slightly anteriorly, greatest thickness material ante:rior simulating spondylium. Pad secondary material narrows 

medially to diamond-shaped ridge. Median portion 

muscle field slightly elevated and parallel-sided; covering about one-half total area muscle attachment. 

Paired, narrow diductor impressions lateral to median scar. Small pedicle ,callist at ,posterior part delthyrial cavity. Anterior and lateral margins strongly crenulated. 

Brachial valve interior.-Cardinalia consist of 

rounded cardinal process (narrow, linear cardinal 

process present in small individuals) rising from 

notothyrial platform laterally bounded by short, 

stout hrachiophores laterally fused to valve posterior margin. Dental sockets bounded anteromedially 

by brachiophores, posteriorly by interarea, are relatively narrow. Broad myophragm, rounded in cross 

section, descends anteriorly from notothyrial platform to point slightly anterior of midlength. Adductor impressions divided medially by low myophragm and la;terally by paired, laterally diverging 

myophragms. Laterally diverging myophragms 

marked posteriorly but decrease in height anteriorly 

and serve to divide adductor impressions into two 

scar pairs. Lateral pair adductor impressions about 

half length of medial pair, both pairs relatively elongate in outline. Anterior and lateral margins strongly crenulate. 

Measurements.-Scatter diagram of length versus 

width of brachial valves is es,s-entially linrear (fig. 2), 

although the short size interval represented by sample precludes conclusions as to linearity or departure 

therefrom of growth curve as a whole. Sample appears normally distributed which suggests that small 

specimens have been abstracted at growth site or 

that this portion of the original population has undergone transport and sorting. Slope of growth line 

about 50° and amount of dispersion not grea,t for this 

type of orthoid. 

Comparison.-Adequate comparative material is 

not available with which to ascertain specific identity of the Maine material. It is not markedly dissimilar to previously described Ptychopleurella s. s. Bpecies ; likely that group of species assigned to this 

genus needs revision. 

Occurrence.-USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Base of Hobbstown Formation (Upper Silurian). 

20 

(/) 

a: 

w 

1-

w 

~ 

...J 

...J ·. ~ 10 

~ J' . : :.. . :£ 

1-

(!) 

z 

w 

...J 

0 

0 10 20 

WIDTH, IN MILLIMETERS 

FIGURE 2.-Relationship of length versus 

width in impressions of interior of 

brachial valves of Ptychopleurella sp. 

USGS loc. 3479-SD, Spencer Lake quadrangle, Somerset County, Maine. 

Distributinn.-Gen us known from Europe and 

North America. 

Figured specimens.-USNM 125801A-B, 125802A, 

125803B, 125804. 

Measured specimens.-USNM 125801-125803. 

Unmeasured specimens.-USNM 125805. 

Family DINORTHIDAE 

Genus VALCOUREA Raymond, 1911 

Valcourea sp. 

Plate 2, figure's 18-22 

Exterior.-Pedicle valve concave, brachial valve 

evenly convex, latter has greater degree of curvature 

than former. Greatest width at straight hinge line. 

Pedicle valve interarea steeply apsacline, brachial 

valve interarea anacline. Pedicle valve interarea 

about three to four times longer than that of brachial valve. Valve outline subcircular to elliptical, but 

deformation helps determine outline. A study of 

relationship between length and width in a number 

of species of Valcourea and in material from Maine 

(fig. 3) indicates that degree of variability in material from Maine is far greater than in other shell 

populations. The much greater variability of Maine 

specimens should probably not be ascribed to biologic cause but rather to deformation. Relation between length and width changes with size. Width increases at greater rate than length, that is, shells 

tend to become subcircular with increasing size from 

originally transverse condition. Delthyrium closed 

by convex pseudodeltidium and notothyrium closed 

by convex chilidium. Lateral margins of valves evenly rounded. Brachial valve bears broad sulcus and 

pedicle valve corresponding low fold. Shells stro-
SYSTEMATIC PALEONTOLOGY 9 

phomenoid in appearance. Costellae increase by bifurcation, crossed by fine concentric lines. Anterior 

commissure faintly uniplicate and crenulate. 

Pedicle valve interior.-Short dental plates laterally bound deeply impressed muscle field. Hinge teeth 

short, rounded, supported by dental lamellae. Muscle 

field tripartite, consisting of median, narrow adductor impression with subparallel sides, laterally 

bounded by relatively elongate diductor impressions 

that eXJtend anteriorly beyond adductor impression 

area. Anterior part adductor impression slightly 

elevated above corresponding parts of diductor 

impressions. 

Brachial valve interior.-Cardinalia consist of 

rounded cardinal process anteriorly joining with 

rounded median septum and short, stubby brachiophores. 

M easurements.-Scatter diagram of length versus 

width for specimens from Maine shows an abnormally great dispersion for an orthoid brachiopod 

(fig. 3). To check this seemingly abnormal distribu20 (/) 

a: 

w 

._ . w 

~ 

:J 

...J 

:iE 

~ 10 

r." 

._ 

(.9 

z 

w 

...J 

...J 

...J 

w 

J: 

en 

00 10 20 30 

SHELL WIDTH, IN MILLIMETERS 

FIGURE 3.-Relationship of length versus width of shell 

impressions of Valcourea sp., Kennebec Formation, 

USGS loc. 4317-CO, Brassua Lake quadrangle, Somerset County, Maine. 

tion, five undistorted samples belonging to four species of the genus were measured. The study of five 

plots obtained from undistorted samples showed conclusively that the sample from Ma.ine had an abnormally high degree of dispersion in terms of biologic 

variation. Abnormal degree of dispersion is ascribed 

to distortion of specimens by mechanical means. The 

growth line slope for specimens from Maine is relatively meaningless because the amount of mechanical deformation undergone by specimens has completely obscured and a.ltered their form. The sample 

from Maine is normally distributed, but it is not 

possible to ascribe distribution to either transportation or abstraction of small specimens in situ. 

Discussion.-The material from Maine has undergone a great amount of deformation making it impossible to assign specifically because the form of the 

exterior is the basis used for discriminating between 

species of the genus (Cooper, 1956). 

Occurrence.-USGS loc. 4317-CO, Brassua Lake 

quadrangle, Somerset County, Maine. 

StTatigraphic location.-Kennebec Formation 

(middle Middle Ordovician). 

Distribution.-The genus is restricted to North 

America and Scotland. 

Figured specimens.-USNM 125750A, B; 125751, 

125752A-C (A, B are unfigured external impressions of the figured impression of the interior). 

Measured specimens.-USNM 125750-125752, 

125754-125766, 125768-125771, 126328. 

Unfigured specimens.-USNM 125767N, 1257758, 

125776T. 

Suborder DALMANELLOIDEA 

Superfamily DALMANELLACEA 

Family DALMANELLIDAE 

Genus RESSERELLA Bancroft, 1928 

Resserella sp • 

Plate 2, figures 23-27 

Exterior.-Brachial valve relatively flat, pedicle 

valve convex, naviculate in form. Straight hinge line, 

greatest width anterior of hinge line near midlength. 

Brachial valve interarea very steeply hypercline, 

pedicle interarea gently apsacline. Delthyrium and 

notothyrium apparently unmodified by plates. Anterior margin rectimarginate, crenulate. Lateral 

margins evenly rounded, shell outline slightly elongate to subcircular. Costellae increase by bifurcation. 

Pedicle valve interior.-Short dental lamellae laterally bound posterior half of muscle field. Hinge 

teeth elongate, terminally crenulate. Muscle field tripartite with narrow, median, parallel-sided adductor impression laterally flanked by a.nteriorly expanding diductor impressions. Anterior and lateral 

shall margins strongly crenulate. 

Brachial valve interior.-Cardinalia consist of 

prostrate, posteriorly directed cardinal process laterally flanked by stubby brachiophores and anteriorly 

joining low myophragm with rounded cross section. 

Cardinal process cleft medially by narrow slit. Dental sockets floored with crenulated fulcra} plates. 

Medial face dental socket formed from brachiophore 

and posterior face by hinge line. Adductor impression divided medially by myophragm, bounded laterally by low ridges of secondary material that extends 

anteriorly from brachiophore base. Adductor impressions quadrilobate, divided by low ridge secon-
10 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

dary material extending normal to midline. Anterior 

pair larger; whole adductor field elliptical in outline. 

Anterior and lateral margins of shell strongly 

crenulate. 

Discussion.-The available material is inadequate 

for specific determination. 

Occurrence.-USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somersert County, Maine. 

Stratigraphic location.-Base of Hobbs,town Formation (Upper Silurian). 

Figured specimens.-USNM 125772-125774. 

Unfigured specimens.-USNM 125778-125780, 

126112. 

Resserrella? sp. 

Discussion.-Single specimen from Hardwood 

Mountain Formation assigned questionably to Resserella because specimen has characteristic flat 

brachial valve and naviculate pedicle valve of genus. 

Occurrence.-USGS loc. 3488-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian). 

Unfigured specimen.-USNM 125777. 

Subfamily ISORTHINAE 

Genus ISORTHIS Kozlowski, 1929 

lsorthis sp. 1 

Plate 2, figures 28-32 

Exterior.-Unequally biconvex shells, pedicle 

valve having greater degree of convexity. Straight 

hinge line, greartesrt shell width near midlength. Pedicle valve interarea apsacline, brachial valve interarea anacline. Shell outline subcircular. 

Brachial valve faintly sulcate. Anterior margin 

gently sulcate, crenulate. Pedicle valve interarea 

about two to three times as long as that of brachial 

valve. Shell lateral margins rounded. Cosrtellae increase by bifurcation, crossed by concentric growth 

lines. Shell punctate. 

Pedicle valve interior.-Hinge teeth bladelike, 

supported by short dental lamellae that form lateral 

margins of elongate muscle field. Muscle field contains elongate median adducior track whose anterior 

portion is raised up from floor of valve by secondary 

material, and paired, lateral, elongate diductor impressions which extend slightly anterior of adductor 

track margin. Shell interior relatively smooth, does 

not reflect external costellae. 

Brachial valve interior.-Cardinalia consists of 

small prostrate cardinal process located between two 

large, bladelike, laterally diverging brachiophores. 

Brachiophores connected posteriorly to fulcra! plates 

which serve to floor dental sockets. Posterior face of 

dental socket formed by palintrope. Brachiophores 

supported basally by brachiophore plates which diverge laterally, parallel to brachiophores. Sharp 

ridges extend anteriorly from brachiophore plates 

which surround muscle field laterally and finally converge medially before attaching to rounded, low myophragm which bisects muscle field. Myophragm 

extends from base of cardinal process to about midlength or to position slightly posterior. Muscle field 

quadripartite adductor impressions transversely divided by low ridges uniting medially with myophragm. Anterior and lateral margins finely 

crenulated. 

Comparison.-Moose River synclinorium isorthids 

represented by relatively inadequate material, but 

meaningful comparisons may still be made. I. sp. 3 

possesses a relatively narrow median adductor track 

in the pedicle valve which contrasts greatly with the 

relatively broad median adductor tracks of I. sp. 1 

and 2. Subciroular adductor field in brachial valve of 

I. cf. I. perelegans contrasts strongly with the longitudinally elongate adductor field present in I. sp. 1, 

2, and 3. Pedicle muscle field in I. sp. 2 widens ante,riorly in manner, differing considerably from /. 

sp. 1. /. sp. 1 has pedicle valve internal morphology 

similar in all regards to /. arcuaria, but inadequate 

material availalble makes specific determination 

premature. 

Occurrence.-USGS loc. 3479-SD, Spencer Lake 

quadrangl,e, Somerset County, Maine. 

Stratigraphic location.-Base of Hobbstown Formation (Upper Silurian). 

Figured specimens.-USNM 125827-125829. 

Unjigured specimens.-USNM 125830, 125831. 

Isorthis sp. 2 

Plate 2, figures 33-35 

Discussion.-Single brachial valve from Hardwood Mountain Formation and single pedicle valve 

from Parker Bog Formation have characteristic 

internal features usually associated with Isorthis. 

Material too poor for specific identification. 

Comparison.-See I. sp. 1. 

Occurrence.-USGS loc. 3495-SD and 3487-SD, 

Spencer Lake quadrangle, Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian), and Parker Bog Formation (Lower Devonian). 

Figured specimens.-USNM 125831A, 125826. 

Unjigured specimens.-USNM 126329. 

lsorthis sp. 3 

Plate 3, figures 1-16 

Exterior.-Valves unequally biconvex with pedicle valve about twice as deep as brachial valve. Valve 

outline tends to be transversely suboval. Hinge line 
SYSTEMATIC PALEONTOLOGY 11 

straight and less than maximum width which occurs 

about midlength. External ornament not preserved. 

Pedicle valve interior.-Hinge teeth supported by 

short, slightly divergent dental lamellae which are 

continuous anteriorly as subparallel or slightly anteriorly converging muscle bounding ridges. Diductor tracks enclosed by these ridges relatively 

narrow and rounded, separated by rounded ridgelike myophragm medially. DiduCJtor tracks extend 

about lj3 to 2j5 length of valve and not deeply impressed or elevated on platform anteriorly. Anterior 

very faintly crenulated by costae at margin of valves. 

Brachial valve interior.-Sockets expand and diverge anterolaterally with what appear to be poorly 

developed fulcral plates at bases. Cardinal proces~s 

base narrow, ne~arly linear; distal end not exposed. 

Adductor muscle scars enclosed by relativ'ely broadly set-apart muscle bounding ridges that may or may 

not continue around posterior and anterior pairs. 

Two pairs about equal size and delineated by small 

ridges between posterior and ante:rior pairs; ridges 

are normal to midline. Low myophragm divides subtriangular posterior pair adductors. Dorsal margins, 

like those of pedicle valve, faintly crenulated by impress of costellae. 

Comparison.-See I. sp. 1. 

Occurrence.-USGS loc. 5587-SD, 5583-SD, 5586-

SD, Attean quadrangle, Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain 

Formation (Upper Silurian). 1

Figured specimens.-USNM 160113-160119. 

lsorthis cf. I. perelegans (Hall, 1859) 

Plate 3, figure 17 

Discussion.-Sin.gle brachial valve closely resembles I sort his perelegans; convex, subcircular, slightly wider than long. Cardinal process flanked by widely diverging brachiophores that join anterolaterally 

with broadly srpaced muscle bounding ridges which 

enclose rhomboidal muscle impression consisting of 

posterior and anterior adductor pairs. 

Comparison.-See I. sp. 1. 

Occurrence.-USGS loc. 3499-SD, Spencer Lake 

quadrangle, Somers·et County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian). 

Figured specimen.-USNM 125813. 

Genus LEVENEA Schuchert and Cooper, 1931 

Levenea sp. 

Plate 3, figures 18-20 

Exterior.-Biconvex shells with pedicle valve having greater convexity. Outline subcircular. Hinge 

line straight; greatest width a;bout midlength. Lateral margins rounded; anterior commissure rectimarginate, crenulate. Radial costellae. 

Pedicle valve interior.-Dentallamellae short and 

almost obsolete. Hinge teeth form no't shown on 

Maine material. Muscle field tripartite with broad, 

anteriorly expanding median adductor track, whose 

anterior portion is raised up from valve floor by pad 

of secondary material, and relatively narrow, paired 

diductor tracks inclined almost normally to shell, 

placed in secondary material which fills valve posterior portion. Pallial marks paired; diverge anterolaterally from point where diductor impressions join 

adductor impression. 

Brachial valve interior .-Cardinalia consist of 

cardinal process on bladelike base flanked laterally 

by stout brachiophores. Anteriorly brachiophores 

give rise to bladelike brachiophore plates. Anteriorly from brachiophore plates are subparallel musclebounding ridges. Muscle field medially divided by 

prominent, rounded myophragm. 

Comparison.-Available material too poorly preserved and fragmentary for specific identification, 

but form res·embles L. subcarinata (Hall. 1857). 

Occurrence.-USGS loc. 3499-SD, Spencer Lake 

quadrangl,e, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian). 

Figured specimens.-USNM 125811B, 125812, 

125814. 

Unfigured specimens.-USNM 125815 A-G. 

Unidentified orthoid 

Plate 3, figure 21 

Discussion.-The only fossil recovered from the 

Lobster Mountain volcanics indicates a Middle Ordovician or younger age (presumably pre-Givetian in 

the absence of Givetian or younger marine beds in 

this region). 

Occurrence.-USGS loc. 3280-SD, North East 

Carry quadrangle, Piscataquis County, Maine. 

Figured specimen.-USNM 126473. 

Family DICAELOSIIDAE 

Genus DICAELOSIA King, 1850 

Dicaelosia sp. 

Plate 3, figure 22 

Exterior.-Small shells with s1trongly emarginate 

anterior margin ; straight hinge line much narrower 

than greatest width which occurs forward of midlength. Shells biconvex with pedicle valve having 

somewhat greater convexity than brachial valve. 

Valves sulcate. Costellae and concentric growth lines. 

Comparison.-N o information regarding specific 

identity of Maine material is available because of 
12 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

fragmentary condition. No inte,riors of either valve 

ar~e available for study. 

Occurrence.-USGS lac. 3479-SD, 3488-SD, and 

3499-SD, Spencer Lake quadrangle, Som~erset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian), base of Hobbstown Formation (Upper Silurian), and Beck Pond Limestone 

(Lower Devonian). 

Figured specimen.-USNM 125810. 

Unfigured specimen.-USNM 126330. 

Family RHIPIDOMELLIDAE 

Subfamily RHIPIDOMELLINAE 

Genus DISCOMYORTHIS Johnson, 1970 

Discomyorthis musculosa solaris (Clarke, 1907) 

Plate 3, figures 23-25 plate 4, :figures 1-3 

Rhipidomella musculosa Hall var. solaris Clarke, 1907, p. 

284, figs 1, 3, not fig. 2; Clarke, 1909, p. 88, pl. 21, figs. 

8, 10-11, not fig. 9. 

Exterior.-Subcircular to transversely elliptical 

shells with narrow hinge line and interarea. Brachial valve more convex than almost flat pedicle valve. 

Pedicle valve commonly bears broad, low median sulcus. Greatest width near midlength. Interare~a concave, gently apsacline in pedicle valve orthocline in 

brachial valve. Pedicle valve interarea about three 

times as long as that of brachial valve. Delthyrium 

unmodified by plates, but filled by cardinal process. 

Pedicle valve beak slightly incurved. Anterior commissure uniplicate and crenulate. Costellae increase 

by bifurcation. Growth lines concentric. Shell 

punctate. 

Pedicle valve interior.-Stout hinge teeth bo,rder 

delthyrial cavity and project dorsally from anterior 

portion narrow interarea. Hinge teeth supported by 

short dental lamellae ; almost obs1olescent in large 

specimens. At base of dental lamellae lateral ridge 

continues anterolaterally to point slightly posterior 

of midlength and then turns anteromedially almost 

to surround muscle field. Muscle attachment area 

large, subcircular to transvers~ely elliptical in outline, 

commonly reaches three-qua~rters of distance to anterior margin. Muscle field bisected by sharp low 

myophragm. Large, flabellate diductor impressions 

surround small, elongate, pos~teriorly situated adductor impressions. 

Several radially disposed myophragms traverse 

diductor impressions. Posterior face delthyrial cavity 

occupied by pedicle callist; which is located on slightly raised pad of secondary material. Umbonal cavities commonly almost complEtely filled with secondary material. Anterior a:ad lateral shell margins 

crenulated by flat crenulae which are grooved on 

upper faces. Valve interior, where not occupied by 

muscle impressions, relatively smooth due to deposition of secondary material. 

Brachial valve interior.-Cardinalia consist of 

erect cardinal process which swells distally, has 

trifid posterior face, and joined posterolaterally with 

bladelike brachiophores. Brachiophores supported by 

brachiophore plates which form outer edge of dental 

sockets. Extending anteriorly from base of cardinal 

process is broad, low myophragm which bisects adductor impressions. Four adductor imp,ressions, but 

posterior and anterior pairs not well differentiated. 

They extend anteriorly to position short of midlength. Anterior and lateral margins bear flat crenulae which may be grooved on upper faces. 

Measurements.-The length :width scattergrams 

for Maine specimens show essentially linear growth 

curve with slope about 50° (figs. 4C, D). Similar 

material from three Appalachian localities has a 

much smaller degree of dispersion than the Maine 

material, strongly suggesting that the Maine material is mechanically deformed to a large degree. 

The Maine material is normally distributed, which 

suggests that either small specimens have been abstracted or transportation and sorting has taken 

place. Degree of dispersion of the more highly convex brachial valves is greater than the relatively 

flat pedicle valves from Maine which suggests 

crushing has been important in producing dispersion. Amount of absolute variation increases with 

size increase, but there is no suggestion that percentage variation increases with size. 

Dis,tribution of three samples from the Appalachians suggests all have similar slopes and growth 

curves ; degree of dispersion is of the same order of 

magnitude. 

Relation between length and width of the diductor 

muscle field of the pedicle valve was studied (fig. 

4E). The growth curve slope is about 40° but the 

degree of dispersion is great which prevents, with 

present samples, estimating amount of departure 

from linearity. Considerable variation between diductor length and width suggests that this relation 

is not useful in specific characterization of rhipidomellids. It can be inferred that size and form of 

diduetor field were not critical to the animal. 

Figure 4F shows the relationship between pedicle 

valve width and interarea width. Available information suggests a relatively linear relation; amount of 

dispersion is small. Slopes show a significant degree 

of difference between samples. Differences in slope 

are about 13° for D. musculosa solaris and about 25° 

for D. oblata. This relation emphasizes that interarea width appears to be a rhipidomellid character 

which remains relatively constant in any one sam-
SYSTEMATIC PALEONTOLOGY 13 

ple and has a wide variation span within a generic 

grouping. Inadequate information is available to 

determine W'hether differences should be accorded 

specific or generic rank. 

Relationship between ang,le included by diductor 

muscle field (lateral ridge angle) and pedicle valve 

width is very variable (fig. 4G). The angle does not 

change consistently with change in specimen size. 

Degree of dispersion between samples is very great, 

but the significance of this differenee is not apparent. 

Relationship of left lateral ridge angle to right 

la,teral ridge angle is random, as expected, of bilaterally syrnmetrical shells (fig. 4H) ; all samples 

exhibit about the same degre,e of dispersion and 

aibout the saJme angular relationships. 

Relationship of pedicle valve width and width of 

diductor field is linear (fig. 4B), having a low degree 

of disper,sion, indicating muscle field increases 

linearly with inc,rease in shell width. Relationship 

between brachial valve width and angle included between the brachiophores is essentially random (fig. 

4A), suggesting it remains constant with shell width 

increase. 

Discussion.-This subspecies was first described 

by Clarke (1907), as a variety of Rhipidomella 

musculosa (Hall, 18'57), from material collected by 

Olof Nylander. In the original description, "Moosehead Lake, Baker Brook Point; Brassua Lake, east 

side; Moose River at Stony Brook, Me." listed as 

localities (Clarke, 1907, p. 284). Later Clarke gave 

the same lojcality list (Clarke, 1909, p. 88) ; on page 

208 of sante volume, however, localities were assigned to four figured specimens (three previously 

figured in Clarke, 1907) -figures 8, 10, and 11 cited 

from Tomhegan Point, Moosehead Lake and figure 

9 from Jackman farm. Because rocks and fnssils of 

Oriskany age only occur on Tomhegan Point and 

Discomyorthis musculosa solaris is limited in range 

to beds of Schoharie age in this region, it seems 

clear that the specimens represented by figures 8, 10, 

and 11 were collected from beds of Schoharie age 

(probably on Baker Brook Point). Figure 9, representing a brachial valve, possesses the cardinalia 

and other eharacte,rs of Pla.tyorthis; therefore, it is 

reasonable that it was collected f 1

rom beds of Oriskany age at Jackman farm. 

Clarke's original description indicates that he 

founded his variety [sic] upon the characters of the 

pedicle valve: "These are all small shells with the 

enormous adductor [sic-adductor-diductor] scar in 

a state of high development. The shells are somewhat 

less circular, more transverse than in the New York 

and Grande Greve Oriskany specimens of R. musculosa, but their specific identity is not greatly veiled" 

(Clarke, 1907, p. 284). It is recommended that D. 

musculosa solaris (Clarke, 1907) be retained for the 

form whose pedicle valves are figured in accordance 

with his implied intent. 

Comparison.-Discomyorthis musculosa has a 

slightly wider interarea than D. musculosa solaris, 

but relationships between pedicle valve length and 

width and pedicle valve muscle field are vPry similar 

in both form's. D. oblata tends to have a smaller muscle field in the pedicle valve and wider interarea than 

does D. musculosa solaris. Discomyorthis alsa, although having characteristic marginal crenulations 

of Dalejina and Discomym·this, does have a far wider 

interarea than do Discomyor·this oblata, Discomyorthis musculosa, or the form from Maine. Interarea 

of Discomyorthis eryna is similar to Discomyorthis 

alsa and may prove to be conspecific when adequate 

material of both species is studied. 

Occurrence.-USGS locs., 2723-SD, 2730-SD, 

2750-SD, 2752-SD, 2814-SD, 2820-SD, 2839-SD, 

2840-SD, 2842-SD, 2852-SD, 2873-SD. Brassua 

Lake quadrangle, Somerset County, Maine. 

Stratigraphie location.-Tomhegan Formation 

(Lower Devonian). 

Distribution.-N orthern Maine (Tomhegan Formation), northern New Hampshire (Littleton Formation), possibly Green Pond area of New Jersey if 

Kanouse Sandstone "Schizophoria sp. cf. S. striatula 

( Schlotheim) " Weller ( 1903) belongs to this species, 

and possibly "R. alsa? Hall" of Dunbar (1919) from 

western Tennessee (Camden Chert) . 

H olotype.-The interior impression of a pedicle 

valve figured by Clarke ( 1907, p. 284, right side of 

page, NYSM 8505) is here selected as the :holotype. 

Figured specimens.-USNM 125806-125809. 

Unfigured specimens.-USNM 126317-126327. 

Measured specimens.-USNM 125806-125809, 

125816. 

Discomyortbis sp. 

Plate 4, figure 10 

Discussion.-S.pecifically unidentifia:blP Discomyorthis specimens have been obtained from Beck Pond 

Limestone (moderate size, up to 31;2 em wide, relatively short hinge line, relakively restricted pedicle 

valve muscle field) and Discomyorthis sp. from 

McKenney Ponds Member of Tarratine Formation 

(moderate size, flat pedicle valve, relatively convex 

brachial valve, short hinge line, broadly flabellate 

pedicle valve muscle field). 

Occurrence.-USGS locs. 3499-SD, Spencer Lake 

quadrangle, 2810-SD, 2806-SD, 2864-SD, Pierce 

Pond quadrangle, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Liinesrtone 
14 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

40 40 

A B en 

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BRACHIOPHORE ANGLE, IN DEGREES DIDUCTOR WIDTH, IN MILLIMETERS en 

a: en w 30 a: 30 1- w w c 1- D ~ w 

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BRACHIAL VALVE WIDTH, IN MILLIMETERS PEDICLE VALVE WIDTH, IN MILLIMETERS 

en 30 I 

a: 

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DIDUCTOR WIDTH, IN MILLIMETERS 

FIGURE 4.-Scattergrams for Discomyorthis musculosa solaris (Clarke, 1907) from the Tomhegan Formation. USGS loe. 

2750-SD, Brassua Lake quadrangle, Somerset County, Maine. 
SYSTEMATIC PALEONTOLOGY 

40r--------,--------, 40~------~-------.--------,-------~--------r-------, 

F t/) 

0: 

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0 10 20 ~Lo ________ s~o--------~7o--------~s~o~------~go~------~1o~o~----~110 

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a: 

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w 

INTERAREA WIDTH, 

IN MILLIMETERS 

H 

0 50~-------~--------~--------~---------1 

z 

w 

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w 

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20L-------~--------~--------~--------~ 

20 30 40 50 60 

RIGHT LATERAL RIDGE ANGLE, IN DEGREES 

LATERAL RIDGE ANGLE, IN DEGREES 

t/) 

w 

w 

a: 

{9 

w 

50.--------,------~,--------.------~ 

I 

0 40~------~------~-+--~-----+~~----~ 

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ILL. 

w 

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~0L ________ 2~0--------~3L0--------4~0~------~5Q 

RIGHT BRACHIOPHORE ANGLE, IN DEGREES 

FIGURE 4.-Continued. 

15 
16 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

(Lower Devonian) and McKenney Ponds Member 

of Tarratine Formation (Lower Devonian). 

Figured specimen.-USNM 125823. 

Unfigured specimens.-USNM 125821A,B, 

125822A,B. 

Genus DALEJINA Havlicek, 1953 

Dalejina sp. 1 

Plate 4, figures 6-9 

Discussion.-The base of the Hobbs town Formation yielded one pedicle valve and one brachial valve 

possessing characters of D·alejina including flat crenulations with grooves on inner faces. Paucity of material and present difficulty in accurately defining 

already named species make it inadvisable to identify specifically Maine material. This subequally biconvex form, having short hinge line, small size, 

relatively small and nonflabella.te pedicle muscle fieJd, 

is similar to the Silurian species D. cliftonensis, D. 

newsomensis, and D. subtriangularis. Costellae of the 

form from the Hohbstown Formation are somewhat 

coarser than in the form from the underlying Hardwood Mountain Formation (species 2). The outline 

of Hobbstown Formation specimens is more like that 

of D. suhtriangularis than of any other species mentioned above. 

Occurrence.-USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somersert Counrty, Maine. 

Stratigraphic location.-Base of Hobbstown Formation (Upper Silurian). 

Figured specimens.-USNM 125821, 125822. 

Dalejina sp. 2 

Plate 4, figures 4, 5 

Discussion.-A few poorly preserved specimens 

having Dalejina characters, including crenulate internal margin on which crenulae are flat and have 

grooved upper faces, were obtained from several 

localities in the Hardwood Mountain Formation. 

Pedicle and brachial valv,es subequally biconvex, 

short hinge line, relatively small and nonflabellate 

pedicle valve muscle field, and relatively fine costellae. Shell outline subcircular. Specimens similar to 

Silurian species enumerated under description of 

Dalejina sp. 1 from the base of the Hobbstown Formation; like it, inadequate for making specific identification. Hardwood Mountain Formation material 

has somewhat finer costellae than those from the base 

of the Hohbstown Formation. 

Occurrence.-USGS locs. 2950-SD and 3469-SD, 

Spencer Lake quadrangle, Som·erset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian). 

Figured specimen.-USNM 125824. 

Unfigured specimens.-USNM 126346-126349, 

126440-126442. 

Dalejina? sp. or Discomyortbis? sp. 

Discussion.-Parker Bog Formation yielded few 

very poorly preserved, highly deformed rhipidomellids that probably belong to Dalejina or Discomyorthis. Not possible to make positive assignment without information regarding crenulations along internal margins. Specimens have relatively short hinge 

line. 

Occurrence.-USGS loc. 3477-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Parker Bog Formation 

(Lower Devonian) . 

Subfamily PLATYORTHINAE 

Genus PLATYORTHIS Scbucbert and Cooper, 1931 

Discussion.-In addition to the distinguishing 

characters of Platyorthis, described by Schuchert 

and Cooper (1931, p. 246) including the plano-convex profile and large, posteriorly reclining cardinal 

process, bifurcating crenulations occur along internal margins. These crenulations are unlike those of 

other members of the Rhipidomellidae, and therefore, serve to distinguish even fragmentary platyorthid material from other genera of the family. 

Platyortbis planoconvexa (Hall, 1859) 

Plate 4, figures 11-18 

Platyorthis planoconvexa (Hall, 1859), see Boucot, 1959b, 

p. 739-740, pl. 90, figs. 3-10. 

Exterior.-Brachial valve flat, pedicle valve convex and has carinate form. Shell outline subcircular 

with greatest width near midlength. Hinge line 

straight, very narrow, interarea small. Pedicle valve 

interarea concave, gently anacline to orthocline; 

brachial valve interarea anacline. Delthyrium unmodified, occupied by projecting cardinal process of 

opposite valve. Pedicle valve interarea about twice 

as long as that of brachial valve. Anterior commissure rectimarginate and crenulate. Pedicle valve 

beak slightly incurved. Costellae increase by bifurcation ; crossed by concentric growth lines. Shell 

punctate. 

Pedicle valve interior.-Stout, bladelike, laterally 

diverging hinge teeth supported by short dental 

lamellae. Hinge teerth posteriorly connected by small, 

horizontal plates flooring crural fossettes with posterior valve margin. Dental lamellae inner faces indented by crural foss·ettes. Umbonal cavities commonly almost filled with secondary material ; consequently dental lamellae tend to become obsolete in 

larger specimens. Muscle field large, flabellate, commonly includes angle of about 30°, reaches from two-
SYSTEMATIC PALEONTOLOGY 17 

thirds to three-quarters distance to anterior margin, 

bisected by low, narrow myophragm. Muscle impressions divided into pair large diductor scars which 

expand anteriorly; divided by number of radially 

disposed, short myophragms into number of sectors. 

Small, elongate adductor impressions, poorly impressed posteriorly, abut pedicle calli st. Pedicle 

callist located on posterior wall of delthyrial cavity 

upon small pad secondary mate~ial. Internal margins •bear crenulae that bifurcate peripherally. Musde field in large specimens bordered laterally by low, 

rounded ridge of secondary material that extends 

anteriorly from base of denrtal lamellae. 

Brachial valve interior.-Gardinalia consist of 

posteriorly directed, terminally bifid cardinal p~rocess 

fused laterally with laterally diverging brachiophores. Brachiophores s.tout, supported by short 

brachiophore plates. Dental socke1ts anteriorly bordered by brachiophores and posteriorly by low ridge 

slightly anterior of interarea. Low ridges diverge in 

slightly anterolateral direction. 

Muscle area transversely elliptical to subcircular 

in outline; restricted to posrberior half of valve. Divided by low, rounded myophragm extending anteriorly to about midlength. Paired adductor impressions elliptical in outline; may be transversely 

divided by pair of low, transverse ridges into four 

impressions. Lateral portions muscle field bounded 

by low ridge of secondary material that enends anteriorly from base of brachiophore plates. 

Measurements .-Relationship between brachial 

valve length and width suggests growth is relatively 

linear. Dispersion of Maine material is several times 

greater (fig. 5A) than undeformed material from 

New York (fig. 5B) suggesting that Maine material 

had linear dimens.ions altered mechanically. Maine 

material i·s normally distributed. 

Comparison.-Orthis lucia Billings, 1874 is a junior synonym of Platyorthis planoconvexa, the former 

being described from the Grande Greve Limestone of 

Oriskany age. No criteria were observed that would 

enable one to discriminate between the platyorthids 

found in northern Maine antd those known elsewhe.re 

in North America. 

Occurrence.-USGS locs. 2701-SD, 3482-SD, 

2721-SD, 2834-SD, 2691-SD, 2698-SD, 2700-SD, 

2813-SD, 2777-SD, 2803-SD, 2719-SD, 2767-SD, 

2860-SD, 3471-SD, 2862-SD, 2711-SD, 2751-SD, 

2770-SD, 2710-SD, 2857-SD, 2870-SD, 2760-SD, 

3474-SD, 2771-SD, 3093-SD, 2810-SD, 3486-SD, 

2806-SD, 3229-SD, Somerset and Piscataquis Counties, Maine. 

Stratigraphic location--Se·boomook Formation 

(Lower Devonian), McKenney Ponds Member of the 

40,-----------r-----------~--------~ 

A 

30r-----------r-----------r---------~ 

.. 

20~----------r---~~~~~·~·~----------~ 

.. 

10 

(fJ 

0: 

w 

r 

w 

~ 

:i 

....J 

~ 0 

~ 30 

:r:: B 

r 

(.!) 

z 

w 

....J 

20 

... 

: . . . 

10 

o~----------~----------~--------~ 

0 10 20 30 

WIDTH, IN MILLIMETERS 

FIGURE 5.-Comparison of length versus width of brachial 

valves of Platyorthis planoconvexa (Hall, 1859). A, lower 

sandstone of the Tarratine Formation, USGS loc. 2701-

SD, Brassua Lake quadrangle, Somerset County, Maine. 

B, Glenerie Limestone, on N.Y. Rte. 9W, 1 miles north of 

Glenerie and 1 mile south of Cockburn, N.Y. 

Tarratine Formation, and the sandstones of the Tarratine Formation (Lower Devonian). 
18 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

Distribution.-The species is known from eastern 

North America. The European specie·s Platyorthis 

circularis is similar in movphology. 

Figured specimens.-USNM 125819, 125820, 

125825. 

Measured specimens.-125817. 

Unfigured specimens.-USNM 125817, 126345, 

125930-125939, 126350-126367. 

Superfamily ENTELET ACEA 

Family SCHIZOPHORIIDAE 

Subfamily DRABOVIINE 

Genus SALOPINA Boucot, 1960 

Salopina LitcLcocki Walmsley, Boucot, and Harper, 1969 

Plate 5, figures 1-11) 

Salopina hitchcocki, Walmsley, Boucot, and Harper, 1969, 

p. 512-513, pl. 71, figs. 1-4; pl. 72, figs. 1-5. 

Exterior.-Unequally biconvex shells with evenly 

convex brachial valve and subconical pedicle valve. 

Hinge line straight, greatest width occurs about 

midlength. Lateral margins of shell rounded. Shell 

outline transve.rsely elliptical. Brachial valve may 

bear low sulcus. Anterior commissure rectimarginate, crenulate; sulcate shells slightly emarginate. 

Brachial valve interarea steeply anacline; pedicle 

valve interarea steeply apsacline. Pedicle valve interarea aJbout four to five times as long as that of 

brachial valve. Del:thyrium unmodified. Costellae increase by bifurcation ; crossed by concentric growth 

lines. 

Pedicle valve interior.-Hinge teeth stout, located 

on medial edge of interarea. Hinge teeth supported 

by short dental lamellae which laterally hound cordate muscle field. Muscle field restricted to delthyrial cavity, located on slightly raised pad of secondary 

material. Ordinarily musde field indivisible, on few 

specimens discernible median adductor track laterally bounded by elongate diductor impressions. Internal margins shell cren ulate. External costellae 

impression not pres,ent on larger shells coated 

with secondary material, hut evident on smalleT 

specimens. 

Brachial valve interior.-Cardinalia consist of 

linear, small, p·rostrate cardinal process laterally 

bounded by laterally divergent brachiophores. 

Brachiophores basaJly supported by laterally divergent brachiophore plates and posteriorly supported 

by fulcra! plates. Fulcra! plates floor dental sockets. 

Low, rounded myophragm extends anteriorly from 

cardinal process in some specimens (where deposition secondary material progressed) and serves, in 

these specimens, to separate deeply impressed muscle field. Such a myophragm commonly absent when 

specimen lacks deeply impressed muscle field. Muscle 

field quadripartite, subcircular outline, transversely 

subdivided by low ridges which join medially with 

myophragm. Muscle impressions subequal, anterior 

adductors larger, bounded late·rally and anteriorly 

by ridge which begins at base of brachiophore plates, 

extends anteriorly then turns medially to join myophragm. Valve interior may be strongly crenulated 

by impression of external cos,tellae, or smooth except for crenulations along internal margins in specimens where secondary material deposited. 

M easurements.-Relationships of length and 

width of both valves are obscure in the sample 

studied because of the great amount of dispersion 

and relatively small size range of specimens (fig. 6). 

Relationship does appear linear. The amount of dispersion appears more than predicted for a small 

orthoid suggesting that physical deformation s,trongly affected specimens. 

Comparison.-See Walmsley, Boucot, and Harper 

(1969) for discussion and comparison of the species 

assigned to Salopina. 

20.-----------.-----------~ 

Brachial valves 

10~----------+-----------~ 

. .·.·: . .. ··. .... rJ) • 0 ::· .: ffi .,' ... 1-

w 

~ 

...J 

~ 0 '-------------'---------------l 

~ 

~ 20.-----------.-----------~ 

:c 

1-

(!) 

z 

w 

...J 

Pedicle valves 

10~--------~+-~~------~ 

. ... .. 

.. 

... 0 •• 

:. '!_.. =·· 0 

10 

WIDTH, IN Ml LLIMETERS 

20 

FIGURE 6.-Comparison of length versus 

width of brachial and pedicle valves of 

Salopina hitchcocki Walmsley, Boucot, 

and Harper, 1969. Tarratine Formation, Somerset County, Maine. 
SYSTEMATIC PALEONTOLOGY 19 

Occurrence.-USGS locs. 2705-SD, 2720-SD, 

2719-SD, 2722-SD, 2704-SD, 2711-SD, 2721-SD, 

27 43-SD, 2775-SD, 2861-SD, 2862-SD, 2872-SD, 

2811-SD, 2729-SD, 2731-SD, 2890-SD, 2860-SD, 

2727-SD, Somerset County, and 2884-SD, Piscataquis County, Maine. 

Stratigraphic location.-Tarra,tine Formation 

(Lower Devonian), and Seboomook Formation 

(Lower Devonian) . 

H olotype.-USNM 125782. 

Figured specimens.-USNM 125781-125783, 

125793A, 125798. 

Unfigured specimens.-USNM 126331-126344. 

Measured specimens .-125784. 

Suborder PENT AMEROIDEA 

Superfamily PENT AMERACEA 

Family GYPIDULIDAE 

Subfamily GYPIDULINAE 

Genus GYPIDULA Hall, 1867 

Gypidula sp. 1 

Plate 5, figures 12-14 

Exterior.-Unequally biconvex shells, pedicle 

valve possessing greater degree convexity. Neither 

fold nor sulcus appears present. Shell outline subcircular with lateral and anterior margins rounded. 

Anterior commissure apparently rectimarginate. 

Hinge line short, probably straight. Pedicle valve 

interarea incurved, very narrow, anacline; that of 

brachial valve not avaHa:ble. Delthyrium appea;rs 

open, unmodified. Shell smooth ; does not appear to 

possess fine ornamentation, spines, or granules. 

Pedicle valve interior.-Small, posteriorly located 

spondylium consis,ts of medially convergent dental 

lamellae supported by short median septum. Median 

septum striated by curved growth lines. Nature of 

hinge teeth not ascertained. Umbonal cavity very 

deep with spondylium near level of commissure. 

Anteriormost part of spond~lium is free. 

Brachial vnlve interior.-Oute1r portions brachial 

plates discrete, extend anteriorly about one-third 

length valve. Inner portions brachial plates short, 

rupparently expand posteromedially. 

Compa,rison.-N onsulcate G. sp. 1 opposed to sulcate G. sp. 2. 

Occurrence.-USGS loc. 3488-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian). 

Figured specimens.-USNM 126508, 126509A. 

Unfigured specimens.-USNM 126373, 12637 4. 

Gypidula sp. 2 

Plate 5, figures 15-23 

Exterior.-Unequally biconvex shells, pedicle 

valve having greater deg·ree convexity. Brachial 

valve bears broad, shallow sulcus, pedicle valve corresponding fold. Shell outline subcircular to elliptical. Anterolateral margins rounded, hinge line short. 

Pedicle valve beak strongly incurved. Interarea very 

restricted. Shell exterior costate, about four costae in 

brachial valve sulcus, four on each flank. Anterior 

margin sulcate, crenulate. 

Brnchial valve interior.-Outer portions brachial 

plates discrete. 

Comparison.-G. sp. 2 (two specimens available 

for study) ornamentation resembles G. coeyma,nensis, but lack of material precludes S'pecific identification. 

Discussion.-The specimen referred to by Woodard (1951, p. 76) and dated as "Siluro-Devonian" is 

shown on plate 5, figures 15-19. 

Occurrence.-USGS loc. 2728-SD, Spencer Lake 

quadrangle, USGS loc. 5587-SD, Attean quadrangle, 

Som·ell'lset County, Maine. 

Strntigra,phic location.-Hardwood Mountain Formation (Upper Silurian). 

Figured specimens.-USNM 125840, 160120. 

Gypidula sp. 27 

Plate 6, figures 1-2 

Exterior.~Unequally biconvex shells with pedicle 

valve having greater degree convexity. Neithe'r fold 

nor sulcus appear present on material. Shell outline 

subcircular, anterior and lateral margins rounded. 

Hinge line short. Pedicle valve beak strongly incurved. Shell exterior costate, about fourteen low, 

rounded costae each valve. 

Pedicle vnlve interior.-Small spondylium located 

posteriorly is supported by mEdian septum extending 

anteriorly about one-half length of valve. Spondylium formed by convergent dental lamellae. 

Brachia,l valve interior.-Short outer portions 

brachial plates rest on valve floor, slightly lateral to 

low, short myophragm w·hich bisects (very poorly 

impressed) muscle field. Outer portions brachial 

plates long and extend anteriorly about one-third 

length of valve, somewhat concave medially. Posterior portions inner brachial plates turn laterally to 

form broad plates. 

Discussion.-The single silicified brachial valve 

from USGS loc. 3485-SD has internal characters of 

Gypidula. Pedicle valve from Joe. 3496-SD assigned 

to Gypidula because of similar ornamentation (no 

brachial valve recovered at this locality). 

Occurrence.-USGS locs. 3496-SD, 3485-SD, 

Spencer Lake quadrangle, Somerset and Franklin 

Counties, Maine. 

Stratigra,phic location.-Hardwood Mountain Formation (Upper Silurian). 
20 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

Figured specimen.-USNM 125842. 

Unfigured specimens.-USNM 126373, 126374. 

Genus SIEBERELLA Oehlert, 1887 

Sieberella beckensis Boucot, n. sp. 

Plate 6, figures 3-8 

Exterior.-Biconvex shells, pedicle valve has 

greatest degree convexity. Outline transversely elliptical. Brachial valve bears broad, low sulcus, pedicle 

valve has corresponding fold. Hinge line straight, 

greatest width near midlength. Pedicle valve interarea steeply apsacline, slightly concave. Anterior 

commissure sulcate, crenulate. Pedicle valve fold and 

corresponding brachial valve sulcus develop at length 

about 6 mm. Brachial valve beak incurved. Angular 

costae, increase by bifurcation, crossed by concentric 

growth lines. About three costae on fold, four to six 

on each flank. Sulcus commonly contains two costae. 

Pedicle valve interior.-Small spondylium consists 

pair small medially conjunct dental lamellae supported by median septum. Median septum extends 

anteriorly about one-half valve length. Anterior 

and lateral portions interior reflect external 

ornamentation. 

Brachial valve interior.-Outer plates medially 

conjunct, supported by median septum, inner plates 

turn laterally to form hinge plates. Dental sockets 

not worked out. Interior impressed by costae. 

Comparison.-Sieberella beckensis is distinguished 

from S. sieberi by latter's greater number of costae 

on fold and sulcus, five to six and four to five respectively. S. roemeri has relatively lower, more rounded 

costae than S. beckensis. 

Occurrence.-USGS loc. 3499-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian). 

Holotype.-USNM 125841A. 

Figured specimens.-USNM 125841, 125839, 

125837, 125838. 

Unfigured specimens.-USNM 126375. 

Family PENTAMERIDAE 

Subfamily PENT AMERINAE 

Genus PENTAMERUS Sowerby, 1812 

Pentamerus? sp. 

Plate 6, figures 9-10 

Exterior.-Evenly convex pedicle valve (no 

brachial valves found), intera1rea almost entirely obsolete. Beak incurved, anacline. Shell exterior 

smooth, open delthyrium appears unmodified. Cardinal margin terebratu1id. 

Pedicle valve interior.-MediaUy convergent dental lamellae form spondylium which extends anteriorly at least one-third valve length. Posteriormost 

portion delthyrial cavity longitudinally w-rinklled. 

Remarks.-Penrding recovery of a brachial valve, 

generic identification is unce·rtain; both Pentamerus 

and Pentameroides have similar pedicle valves. 

Occurrence.-USGS loc. 3475-SD, southern end of 

summit of Limestone Hill, Stratton quadrangle, 

Somerset County, Maine. 

Stra.tigraphic location.-Lime-silicate hornfels of 

Early Silurian age. 

Figured specimens.-USNM 125835-125836. 

Unfigured specimens.-USNM 126372. 

Suborder STROPHOMENOIDEA 

Superfamily PLECTAMBONITACEA 

Family PLECT AMBONITIDAE 

Subfamily PLECT AMBONITINAE 

Genus SOWERBYITES Teichert, 1937 

Sowerbyites? sp. 

Plate 6, figure 11 

Exterior.-Brachial valve gently concave, pedicle 

valve evenly convex. Greatest width at straight hinge 

line. Lateral and anterior margins rounded. Anterior 

commissure rectimarginate. Pedicle valve interarea 

apsacline, that of brachial valve anacline. Radiating 

coarse and fine costellae crossed by concentric 

growth lines. 

Remarks.-A few Kennebec Formation specimens 

possess exteriors resembling Sowerbyites; in absence 

of information regarding internal structures, generic assignment these shells uncertain. 

Occurrence.-USGS loc. 4317-CO, Brassua Lake 

qaudrangle, Somerset County, Maine. 

Stratigraphic location.-Kennebec Formation 

(middle Middle Ordovician). 

Figured specimens.-USNM 126152. 

Unfigured specimens.-USNM 126676. 

Superfamily STROPHOMENACEA 

Family LEPTAENIDAE 

Genus LEPT AENA Dalman, 1828 

Leptaena "rhomboidalis" (Wilckens, 1769) 

Plate 6, figures 12-16 

Leptaena "rhomboidalis" (Wilckens, 1769), s·ee Boucot, 1959b, 

pl. 96, figs. 1-2. 

Exterior.-Posterior portion brachial valve flat, 

anterior portion geniculate, shell has concave appearance. Posterior portion pedicle valve flat to gently convex, anterior portion geniculate. Shell outline 

transversely elliptical. Maximum width situated at 

straight hinge line. Fine, radiating costellae crossed 

by concentric wrinkles. Anterior and lateral margins 

rounded. 

Pedicle valve interior.-Hinge teeth stubby. Muscle field deeply impressed, restrictEd to posterior half 

of valve, subcircular in outline, pair of narrow, median impressions flanked laterally by elliptical, relatively large, diductor impressions. Valve interior 

pustulose and uncorrugated due to deposition secondary material. 
SYSTEMATIC PALEONTOLOGY 21 

Brachial valve interior.-Cardinalia coillSist of 

posteriorly bilobed cardinal process laterally supported by buttress plates, medially joining median 

septum which extends anteriorly to about midlength. 

Muscle field deeply impressed, consists of subcircular, posterior adductor impressions and elongate 

anterior adductor impressions laterally bounded by 

ridge secondary material. Pair of lateral septa occur 

at anterior part of muscle field. 

Occurrence.-USGS loc. 3601-SD, 3400-SD, 2806-

SD, 3497-SD, 2730-SD, 348'8-SD, 3475-SD, 3479-

SD, 3477-SD, 3499-SD, Somerset County, Maine. 

Stratigrraphic location.-Lime-silicate hornfels of 

Early Silurian age, base of Hobbstown Formation 

(Upper Silurian), Ha1rdwood Mountain Formation 

(Upper Silurian), Parker Bog Formation (Lower 

Devonian), Back Pond Formation (Lower Devonian) , McKenney Ponds Member of the Tarratine 

Formation (Lower Devonian), and the Tomhegan 

Formation (Lower Devonian). 

Figurred specimens.-USNM 126141, 126146, 

126127. 

Unfigured specimens.-USNM 127376-127383. 

Family STROPHEODONTIDAE 

Subfamily STROPHEODONTINAE 

Genus STROPHEODONT A Hall, 1852 

Stropheodonta cf. S. demissa (Conrad, 1842) 

Plate 6, figures 17-19 

Exteriorr.-Pedicle valve convex, brachial valve 

concave. Maximum width at straight hinge line. Outline subcircular. Posterior part lateral margin 

straight, anterior part rounded as is anterior margin. Anterior commissure rectimarginate, crenulate. 

Pedicle valve interarea orthocline, that of brachial 

valve hypercline. Interareas both valves short. Costellae with rounded cross sections separated by 

rounded interspaces. Costellae originate by bifurcation, crossed by concentric growth lines and filae. 

Brachial valve interior.-Hinge line wholly denticulate. Cardinalia consist of bilobed cardinal 

process. Muscle field outline subcircular, extends 

anteriorly to about midlength. Median, small, elongate adductor impressions anteriorly pounded by 

breviseptum, laterally and anteriorly bounded by 

two pairs adductor impressions. Peripheral regions 

valve pustulose. 

Comparison.-Ornamentation and forn1 of Maine 

specimens are similar to S. demissa. 

Occurrrence.-USGS loc. 2820-SD, 2750-SD, Brassua Lake quadrangle, Somerset County, Maine. 

Stratigraphic location.-Tomhegan Formation 

(Lower Devonian). 

Figurrcd specimens.-USNM 126145, 126144. 

aff. Stropheodonta ap. 

Plate 6, figures 20-23 

Exterior.-P,ed.icle valve very convex and infla,ted. 

Maximum width located near midlengtn. Hinge line 

straight. Posterior pa,rt lateral margin relatively 

straight, anterior part and anterior margin rounded. 

Anterior commis1sure rectimarginate. Tnterarea relatively short, orthocline. Costellae coarser in umbonal 

region than peripherally, part of this apparent weakening may be due to abrasion. Outline variable. Pseudodelti.dium covers delthyrium. 

Pedicle ~ualve interior.-Hinge line wholly denticulate. No dental lamellae observed although thickenings lateral to muscle field present. Two pits present 

lateral to well-developed median process. Muscle field 

weakly impressed to well impressed, paired posteromedial adductors separated by narrow depression, 

more broadly flabellate anterolateral diductor 

impressions. 

Comparison.-This material does not belong to 

Stropheodonta s. s. as defined by Williams (1953, p. 

34-35) because it lacks the coarse costellation of that 

genus. Unfortunately the available material is inadequate for specific description. 

Occurrence.-USGS locs. 2820-SD, 2750-SD, 

Brassua Lake quadrangle, Somerset County, Maine. 

Stra-tigraphic location.-Tomhegan Formation 

( Lowe'r Devonian) . 

Figured specimens.-USNM 126126, 126153, 

126125. 

Genus LEPTOSTROPHIA Hall, 1892 

Leptostrophia cf. L. magnifica (Hall, 1857) 

Plate 7, figures 1-9) 

Exterior.-Pedicle valve gently convex, brachial 

valve gently concave. Hinge line straight, maximum 

width near midlength. Lateral and anterior margins 

rounded. Anterior commissure rectimarginate. Pedicle valve interarea apsacline, relatively long, brachial valve interarea anacline, relatively short. 

Delthyrium open, includes angle of about 60°-90°. 

Delthyrium apex occupied by secondary material. 

Shell outline subcircular. Fine costellae crossed by 

weak concentric wrinkles. 

Pedicle valve interi01·.-Hinge line wholly denticulate. Cardinal process pits well defined, separated 

medially by ventral process. Ventral process narrow, 

posteriorly fills delthyrial cavity, forms small pseudospondylium. Prominent lateral ridges diverge 

from delthyrial cavity margins, laterally bound 

flabellate muscle field. Lateral ridges include angle 

of 30°-90°. Flabellate muscle field medially divided 

by low rounded ridge which extends anteriorly from 

ventral process to about midlength or position slight-
22 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

ly anterior. Adductor impressions small, elliptical, 

situated just anterior of ventral process. Large, 

flabellate diductor impressions divided into number 

of radial sectors by series of myophragms. Umbonal 

cavities strongly pustulose. 

Brachial valve interior.-Cardinal process lobes 

stout, laterally flanked by large socket plates. Small 

chilidium located between posterior portion cardinal 

process lobes. Wide low rounded ridge descends from 

cardinal process lobes to position posterior of midlength, becoming progressively narrower as it proceeds anteriorly. Adductor imp~ressions relatively 

narrow, extend anteriorly to position slightly posterior of midlength. Umbonal region very pustulose 

lateral of muscle field, remainder of interior crenulated by external ornamentation impress. 

Comparison.-The Maine specimens most strongly resemble L. magnifica, but the material is too poorly preserved for positive specific identification. No 

specimens have been assigned to Leptostrophia in 

the abs.ence of the diagnostic brachial valve interior. 

Occurrence.-USGS loc. 2700-SD, 2705-SD, 2710-

SD, 2813-SD, Somerset Oounty, Maine. 

Stratigraphic location.-Lower sandstone of the 

T'arratine Formation (Lower Devonian). 

Figured specimens.-USNM 126121-126123, 

126142, 12615~ 126159. 

Unfigured specimens.-USNM 126155. 

Leptostrophia? sp. 

Plate 7, figures 10, 11 

Remarks.-A few specimens from several preMoose River Group formations possess internal features that suggest assignment of the specimens to 

Leptostrophia. Cardinal process lobes well de·veloped, 

flanked laterally by prominent socket plates. Hinge 

line at least partly denticulate. Pedicle valve musculature well impressed, bounding ridge~ subparallel 

anteriorly. None of this material well enough preserved to be specifically or generically assigned with 

confidence. 

Occurrence.-USGS locs. 3477-SD. 3499-SD, 

3483-SD, Spencer Lake and Pierce Pond quadrangles, Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian), Parker Bog Formation 

(Lower Devonian), and Beck Pond Limestone (Lower Devonian) . 

Figured specimens.-USNM 126120, 126147. 

Leptostrophia sp. or Protoleptostrophia sp. 

Plate 7, figures 12, 13 

Discussion.-Leptostrophiid pedicle valves are 

abundant in the Lower Devonian formations, but, 

unfortunately, diagnostic brachial valves are rela,. 

tively uncommon. In my opinion it is not possible to 

discriminate pedicle valves of Leptostrophia from 

those of Protoleptostrophia. The diagnostic characters of these genera are discussed under Protoleptostrophia. 

Occurrence.-USGS locs. 2760-SD, 2857-SD, 

2861-SD, 2832-SD, 2883-SD, 2864-SD, 3092-SD, 

2819-SD, 2890-SD, 2877-SD, 2870-SD, 3088-SD, 

2725-SD, 2761-SD, 2711-SD, 2698-SD, 2691-SD, 

2708-SD, 2727-SD, 2749-SD, 2793-SD, 2795-SD, 

2722-SD, 2785-SD, 2831-SD, 2823-SD, 2847-SD, 

2860-SD, 2834-SD, 2777-SD, 2697-SD, 2775-SD, 

2858-SD, Somerset and Piscataquis Counties, Maine. 

Stratigraphic location.-McKenney Ponds Member, upper and lower sandstones of Tarratine Formation (Lower Devonian), and Seboomook Formation (Lower Devonian), Kineo Rhyolite (Lower 

Devonian) . 

Figured specimens.-USNM 126118. 

Genus PROTOLEPTOSTROPHIA Caster, 1939 

Comparison.-The discrimination of Leptostrophia and Protoleptostrophia is based primarily (Williams, 1953, p. 41) on the absence of socket plates 

and a prominent chilidium in the latter; and their 

presence in former. No reliable criteria for discriminating between pedicle valves of these two closely 

related genera have yet been determined. 

Protoleptostrophia cf. P. blainvillei (Billings, 1874) 

Plate 8, figures 1-8 

Exterior.-Pedicle valve gently convex, brachial 

valve flat. Maximum width at straight hinge line. 

Lateral and anterior margins rounded. Anterior 

commissure reotimarginate. Pedicle valve interarea 

apsacline, brachial valve interarea anacline. Shell 

outline transversely elliptical. Fine costellae crossed 

by concentric growth line and subdued wrinkles. 

Pedicle valve interior.-Cardinal process pits well 

defined, medially separated by short ventral process. 

Hinge line wholly denticulate. Lateral ridges bound 

flabellate muscle field, originate lateral to cardinal 

process pits, diverge at angle of about 90° Umbonal 

cavities pustulose. Muscle field large, flabellate, extends to about midlength or a position slightly 

anterior and about half as wide as maximum width. 

Muscle imp·ressions consist of pair small, elliptical 

adductor impressions located just anterior of ventral process and large, flabellate diductor field divided into radial sectors by number of short myophragms. Low ridge originates poste·riorly at base 

of ventral process, bisects muscle field medially. 

Peripheral re·gions of interior crenulated by im·press 

of external ornamentation. 
SYSTEMATIC PALEONTOLOGY 23 

Brachial valve interior.-Cardinalia consist of 

stout cardinal process lobes joined anteriorly by 

broad notothyrial platform, laterally by lateral 

ridges. Notothyrial platform narrows anteriorly to 

median ridge which bisects muscle field. Lateral 

ridges diverge at angle about goo, bound deeply impressed muscle field. Muscle field consists of anteriorly expanding adductor impressions restricted to posterior third of valve. Umbonal regions very pustulose, remainder of valve crenula.ted by imp·ress 

external ornamentation. 

Comparison.-Maine specimens are similar to P. 

blainvillei, but adequate comparative material is not 

available to make positive specific identification. 

Occurrence.-VSGS locs. 2730-SD, 2750-SD, 

2814-SD, 2820-SD, 2839-SD, 2840-SD, 2852-SD, 

2873-SD, Brassua Lake quadrangle, Somerset County, Maine. 

Stratigraphic location.-Tomhegan Formation 

(Lower Devonian) . 

Figured specimens.-VSNM 126140, 126137, 

126154, 126136. 

Unfigured specimens.-VSNM 1273~4, 127393-

1273g5. 

Protoleptostrophia sp. 

Plate 8, figures 9-13 

Exterior.-Pedicle valve gently convex, brachial 

valve flat. Maximum width at straight hinge line. 

Outline subcircular to transversely elliptical. Anterior and lateral margins rounded. Anterior commissure rectimarginate. Pedicle valve interarea apsacline, relatively long; brachial valve interarea anacline, relatively short. Fine costellae crossed by concentric growth lines and weak wrinkles. 

Pedicle valve interior.-Cardinal process pits 

deeply excavated, medially separated by short ventral process. Lateral ridges bound cardinal process 

pits laterally and laterally border flabellate muscle 

field. Narrow ridge extends from ventral process to 

muscle field front. Paired, elongate, small posteriorly 

situated adductor impressions and large, flabellate 

diductor impressions ddvided into radial sectors by 

short myophragms. Muscle field of variable length; 

may extend three-quarters distance to anterior margin and half valve width. Umbonal regions strongly 

pustulose. Valve peripheral portions crenulated by 

external ornamentation impress. Hinge line wholly 

denticulate. 

Brachial valve interior.-Paired cardinal process 

lobes anteriorly bounded by broad, flat, notothyrial 

platform which narrows anteriorly into median 

ridge. Cardinal process lobes laterally bounded by 

diverging lateral ridges which bound muscle field and 

diverge at angle of about goo or more. Umbonal 

region strongly pustulose, remainder of valve crenulated by external ornamentation impress. Muscle 

field deeply impressed, consists of pair of anteriorly 

expanding adductor impressions restricted to posterior half of valve. 

Comparison.-Maine material is too poorly preserved to be specifically identified. 

Occurrence.-VSGS locs. 2824-SD~ 26g9-SD, 

2696-SD, 2719-SD, 2721-SD, 3090-SD, 2810-SD, 

2767-SD, 2729-SD, 2770-SD, 2720-SD, 2718-SD, 

2771-SD, 2701-SD, 2731-SD, Somerset County, 

Maine. 

Stratigraphic location.-Lower sandstone of the 

Tarratine Formation (Lower Devonian). 

Figured specimens.-VSNM 126132-126135. 

Genus STROPHONELLA Hall, 1879 

Strophonella cf. S. punctulifera (Conrad, 1838) 

Plate 8, figures 14-18 

Exterior.-Pedicle valve gently concave, brachial 

valve gently convex in large specimens ; reverse condition true in small specimens, that is resupinate. 

Maximum width at straight hinge line. Pedicle valve 

interarea apsacline, brachial valve interarea steeply 

anacline. Interarea both valves moderate length. 

Lateral and anterior margins rounded. Costellae 

crossed by concentric growth lines. Small pseudodeltidium appears to be present at delthyrium apex. 

Brachial valve chilidium not certain. Anterior commissure rectimarginate. 

Pedicle valve interior.-Hinge line denticulate 

about half its length. Small cardinal process pits located either side of short ventral process. Muscle 

field not discernible on specimen studied. Interior 

crenulated by external ornamentation impress. 

Brachial valve interior.-Cardinal process lobes 

flanked lateraHy by narrow socket plates which parallel hinge line. Short notothyrial platform extends 

anteriorly from cardinal process lobes and narrows 

rapidly. Very short lateral ridges bound muscle field. 

Muscle field restricted to valve posterior, consists of 

subcircular, small adductor impressions. Valve interior very pustulose except periphery which is 

crenulated by e~ternal ornamentation impress. 

Comparison.-Strongly resembles strophonellids 

from Lower Devonian like S. punctulifero. and S. 

ampla. Pedicle valve musculature is not well marked 

in the petaloid fashion characteristic of many strophonellids, but this may be due .to the small size of 

the specimen studied. Dental plates are absent on the 

only pedicle interior studied. 

Occurrence.-VSGS loc. 3477-SD, Pierce Pond 

quadrangle, Somerset County, Maine. 
24 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

Stratigraphic location.-Parker Bog Formation 

(Lower Devonian) . 

Figured specimens.-VSNM 126119, 126157, 

126143. 

Unfigured specimens.-VSNM 126161. 

Superfamily DA VIDSONIACEA 

Family SCHUCHERTELLIDAE 

Subfamily SCHUCHERTELLINAE 

Genus SCHUCHERTELLA Girty, 1904 

"Schuchertella" becraftensis (Clarke, 1900) 

Plate 9, figures 1-11 

Orthotetes becraftensis (Clarke, 1900), p. 51-52, pl. 7, figs. 

15-28. 

Exterior.-Vnequally biconvex shells, brachial 

valve gently convex, pedicle valve subconical. Greatest width near midlength. Hinge line straight. Pedicle valve interarea steeply apsacline to catacline, 

brachial valve inte.rarea steeply anacline. Delthyrium 

closed by convex pseudodeltidium; apical portion 

notothyrium bounded by ribbonlike chilidium. Pedicle valve interarea relatively long, brachial valve 

interarea short. Shells subsemicircular in outline. 

Closely spaced costella.e, rounded in cross ·section, 

separated by rounded interspaces. Costellae originate 

by implantation and bifurcation. Lateral and anterior margins rounded. Anterior commissure ~ectimarginate, cren ulate. 

Pedicle valve interior.-Stout hinge teeth border 

sides of delthyrium, supported basally by own tracks. 

Track may be anteriorly supported by lamellar deposit of secondary material which simulates dental 

lamella. Muscle field semicircular, poorly impressed; 

consists of bilobate field restricted to posterior third 

of valve. Peripheral regions of interior crenula:ted by 

impress of external ornamentation, remainder 

smooth due to deposition of secondary material. 

Brachial valve interior.-Bilobed cardinal process, 

posteriorly extends behind hinge line, fused anteriorly to laterally diverging buttress plates which include 

angle of about 90°. Dental sockets excavated between 

interarea and socket plates. Adductor muscle field 

lightly impressed, extends anteriorly to about midlength. Interior crenulated by external ornamentation impress. 

Comparison.-Maine material appears to be "S." 

becraftensis. Generic assignment not certain because 

of no modern consideration of taxonomy and morphology of Silurian-Devonian orthotetaceans. 

Occurrence.-VSGS locs. 2721-SD, 2719-SD, 

2720-SD, 2810-SD, 3091-SD, 2722-SD, 2806-SD, 

2777-SD, 2767-SD, 2761-SD, Somerset County, 

Maine. 

Stratigraphic loca.tion.-McKenney Ponds Member of the Tarratine Formation, lower sandstone 

of the Tarratine Formation, and Seboomook 

Formation. 

Figured specimens.-VSNM 126139, 126156, 

126124, 126138, 126160, 126162, 126151. 

Unfigured specimens.-VSNM 127367, 127369, 

127371. 

"Schuchertella" sp. 

Plate 9, figures 12-14 

Brachial valve exterior.-Brachial valve evenly 

convex. Maximum width is slightly posterior of midlength. Straight hinge line, interarea steeply anacline, short. Ribbonlike chilidium borders notothyrium. Cos,tella:e originate by bifurcation and implantation. Lateral and anterior margins rounded. Anterior commissure rectimarginate, crenulate. 

Brachial valve interior.-Posteriorly bilobed cardinal process anteriorly fused with buttress plates, 

anteromedially joined by short, rounded septumlike 

ridge. Socket plates diverge at angle of about 90°. 

Muscle field impressed, consists of elongate, elliptical 

adductor impressions medially divided by median 

ridge. Muscle field restricted to posterior third of 

valve. 

Comparison.-Maine material is too fragmentary 

to be specifically identified. 

Occurrence.-VSGS locs. 2814-SD, 2820-SD, 

2750-SD, 2730-SD, Brassua Lake quadrangle, Somerset County, Maine. 

Stratigraphic location.-Tomhegan Formation. 

Figured specimens.-VSNM 126148. 

U nfigured specimens.-USNM 127362-127366, 

127368, 127370, 127372, 127373. 

Genus HIPPARIONYX Vanuxem, 1842 

Hipparionyx sp. 

Plate 9, figures 15-17 

Exterior.-Vnequally biconvex shellts with highly 

convex brachial valve, almost flat pedicle valve. Shell 

outlines subcircula.r. Greatest width near midlength, 

hinge line very narrow. Lateral, posterior, and anterior margins rounded. Anterior commissure rectimarginate, crenulate. Rounded costeUae. 

Pedicle valve interior.-Muscle field flabellate, extends about two-thirds distance to anterior margin 

and one-half distance to lateral margins. Posterior 

portion muscle field bounded by lateral ridges originating posteriorly at base of hinge teeth. Muscle 

field tripartite, consists of posterior, medially situated, elongate adducltor impression anterior of which 

are paired, ellip1tical diductor impressions mediaHy 

separated by low ridge. Peripheral region of valve 

crenulated by external ornamentation impress. 

Brachial valve interim·.-Posteriorly bifid cardinal 

process anteriorly fusred wi1th laterally diverging 
SYSTEMATIC PALEONTOLOGY 25 

buttress plates. Myophragm situated at anterior edge 

of cardinal process. Muscle field impression not 

discernible. 

Comparison.-Maine material is too poorly preserved to be specifi·cally identifiable. 

Occurrence.-USGS locs. 2806-SD, 2810-SD, 

Pierce Pond quadrangle, Somerset County, Maine. 

Stratigraphic location.-McKen.ney Ponds member of the TarrB~tine Formation (Lower Devonian). 

iFigured specimens.-USNM 126150, 126149. 

Unfigured specimens.-USNM 12737 4, 127375. 

Family STROPHOMENIDAE 

Subfamily LEPTAENOIDEINAE 

Genus LEPTAENISCA Beecher, 1890 

Leptaenisca sp. 

Plate 9, figures 18-20 

Pedicle valve exterior.-Pedide valve highl~y convex. Valve outline asymmetrical. Broad cicatrix 

which may have been formed by attachment against 

the stem of a crinoid present on one specimen. Radiating coarse and fine costellae crossed by concentric 

growth lamellae. Lateral and anterior m~argins irregularly rounded. Maximum width is slightly anterior of midlength. Shell transversely elliptical. 

Hinge line relatively straight. Anterior commissure 

rectimarginate. 

Pedicle valve interior.-Muscle field strongly impres'Sed, consists of paired, elongate scars restricted 

to umhonal region. Rounded ridge medially separates 

muscle scars. Muscle field laterally bounded by ridge 

of s·econdary material. Umbonal cavities pustulose, 

due to presence of pseudopunctae. 

Comparison.-Maine specimens are not well 

enough preserved to be identified specifically. However, they do resemble L. australis Kindle. 

Occurrence.-USGS loc. 3499-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian) . 

Figured specimens.-USNM 126128, 126129. 

Suborder CHONETOIDEA 

Superfamily CHONETACEA 

Family ANOPLIIDAE 

Subfamily ANOPLIINAE 

Genus CYRTONISCUS Boucot and Harper, 1968 

Cyrtoniscus nectus (Clark, 1907) 

Plate 9, figures 21-37 

Cyrtoniscus nec.tus (Clarke, 1907), see Boucot and Harper, 

1968, p. 172-173, pl. 30, figs. 6-13. 

Exterior.-Pedicle valve strongly convex posrteriorly, changes convexity abruptly at length of about 

2 mm. Small shells, posterior part of larger shells 

subhemispherical. Shell outline circular to transversely elliptical (deformation greatly distorted outline of specimens from Maine) . Hinge line straight, 

maximum width located near midlength. Brachial 

valve gently concave, does not show abrupt change in 

convexity from posterior to anterior as opposed to 

shape of pedicle valve. Interareas virtually undeveloped except in medial part of pedicle valve where 

anacline. Delthyrial and notothyrial cavities appear 

unmodified. Anterior margin rectimarginate, crenulate. Anterior and lateral margins rounded. Radial 

costae, crossed by fine concentric lines, costae increasing anteriorly by bifurcation and implantation. 

The relation between length and width shown in 

figure 7. One pair of spines extends laterally from 

ears ; from two to ten spines occur along posterior 

margin of pedicle valve. 

Brachial valve interior.-Posteriorly directed, terminally bifid cardinal process, which seals off delthyrium and laterally directed socket ridges. Dental 

sockets formed medially by edge of cardinal process, 

anteriorly by socket ridges, and posteriorly by poorly developed interarea. Median septum not present 

although cardinal process continues anteriorly for 

short distance as notothyria1 platform. Accessory 

septa radiate from cardinalia, reach almost to anterior margin. Anderidia minute. Interior highly pustulose. External ornamentation impress general. 

Pedicle valve interior.-S.tubby hinge teeth continuous with reduced interarea, unsupported by dental plates. Narrow median septum divideR muscle 

field, extends anteriorly to position where change in 

shell convexity takes place. Hollow spine bases present along hinge line. External ornamentation impression present near anterior margin. 

M easurements.-Relationship between length and 

width of pedicle valve (fig. 7) i,s linear, with a high 

degree of dispersion which is probably a funetion of 

mechanical deformation. 

Occurrence.-USGS locs. 2723-SD, 2750-SD, 

2752-SD, 2814-SD, 2820-SD, 2842-SD, 2852-SD, 

2873-SD, Brassua Lake quadrangle, Somerset County, Maine. 

Stratigraphic location.-Tomhegan Formation 

(Lower Devonian) . 

Figured specimens.-USNM 126222, 126223, 

126227-126229, 126231, 126247, 126248, 127391, 

127392. 

Unfigured specimens.-USNM 127361, 127396. 

Family CHONETIDAE 

Subfamily CHONETINAE 

Genus ECCENTRICOSTA Berdan, 1963 

Eccentricosta sp. 

Plate 10, figures 1-7 

Exterior.-Shells concavo-convex in cross section, 

pedicle valve gellltly convex. Maximum width probably near hinge line. Lateral and anterior margins 
26 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

20~----------~--------~ 

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10 20 

WIDTH, IN MILLIMETERS 

FIGURE 7.-Comparison of length versus 

width for pedicle valves of Cyrtoniscus nectus (Clarke, 1907). Tomehegan 

Formation, USGS loc. 2852-SD, Brassua Lake quadrangle, Somerset County, 

Maine 

evenly rounded and crenulate. Pedicle valv·e interarea apsacline, planar. Deltidium fills del:thyrium. 

Deltidium very convex posteriorly. Brachial valve 

inter area not observed ; presumably very narrow. 

Both valves transverse in outline. Relatively coarse, 

undulating costellae originate by implantation peripherally and along posterior margin posteriorly. 

About five or six short spines on ·each side of pedicle 

valve midline. 

Interior.-Interna.I features >poorly preserved on 

available specimens; little noted except presence of 

short, thin septum in interior of pedicle valve beak. 

Remarks.-Berdan (1963, p. 254) noted that costellae originate by bifurcation; I would prefer implantation and bifurcation, as few defined junctions 

were observed in material illustrated by Berdan or 

in specimens from Maine. Maine specimens are too 

poorly preserved to be identified specifically. 

Occurrence.-VSGS locs. 4841-SD, 5583-SD, 

5586-SD, 5995-SD, Attean quadrangle, Somerset 

County, Maine. 

Stra.tigraphic location.-Hard.wood Mountain Formation (Upper Silurian). 

Distribution.-The genus is known from the central Appalachians (Berdan 1963, p. 256), and I have 

observed it in Late Silurian collections from western 

Gaspe, the Fish River Lake quadrangle in Maine, and 

near Marbleton in the Eastern Townships of Quebec. 

Figured specimens.-VSNM 160121, 160126. 

Genus DA WSONELLOIDES Boucot and Harper, 1968 

Dawsonelloides canadensis (BiUinrs, 1874) 

Plate 10, figures 8-12; plate 11, figures 1-7 

Dawsonelloides canadensis (Billings, 187 4) , see Boucot and 

Harper, 1968, p. 166-167, pl. 28, figs. 17-21; pl. 29, 

figs. 1-3. 

Exterior.-Pedicle valve gently convex, brachial 

valve gently concave. Maximum width located at 

straight hinge line. Shell subsemicircular to quadrate in outline. Posterior portion lateral margin 

straight, anterior portion and lateral margin rounded. Pedicle valve interarea apsacline, brachial valve 

interarea steeply anacline to hypercline. Interareas 

both valves moderately long. Convex pseudodeltidium occupies apex of delthyrium. Discrete chilidial 

plates border notothyri urn. Hollow spines border 

lower edge of pedicle valve interarea. Number of 

spines variable, does not exceed ten in specimens 

studied. Anterior margin rectimarginate. Fine costellae interrupted by concentric growth lines, give 

reticulate appearance. 

Pedicle valve interior.-Hinge teeth stout, unsupported by dental lamellae. Distally and medially 

hinge teeth deeply grooved to receive socket ridges 

of brachial valve for articulatory purposes. Median 

septum extends to about midlength anteriorly. Median septum low in delthyrial cavity, but rises rapidly 

to form winglike blade, descends abruptly at about 

one-quarter distance to anterior margin, then extends to about midlength as low septum. Delthyrial 

cavity partly filled by secondary shell material. Muscle bounding ridges laterally border flabellate diductor field. Muscle field about half width of shell, 

extends anteriorly to about midlength. Interior of 

valve very pustulose, due to projecting pseudopunctae. Radiating from posteromedial portion of shell 

are ridges separated by broad, rounded interspaces. 

Ridges bifurcate anteriorly. 

Brachial valve interior.-Posterior facing cardinal process consisting of two cardinal process lobes 

fused medially in large specimens. Short chilidial 

plates occur posterolaterally of cardinal process 

lobes. Anteriorly cardinal process lobes join median 

septum which extends to about midlength. Lateral to 

cardinal process lobes are socket plates which curve 

and extend parallel to hinge line. Pair of anderidia 

in posteromedial portion of interior laterally enclose 

paired adductor field. Anderidia include angle of 

about 60°. Interior very pustulose. Ridges radiate 

from umbonal region, separated by broad interspaces. Ridges bifurcate peripherally. 

Measurements.-Relationship between length and 

width of pedicle valves appears linear (fig. 8), but 

small size of sample precludes definite conclusion. 
SYSTEMATIC PALEONTOLOGY 27 

en 

0: 

50~----------,-----------.-----------, 

40~----------~--------~+---------~ 

w 30~----------~----------+---------~ 

1-

w 

~ 

_J 

_J 

~ 

~ 

:I: .. b 20~----------~----------+---------~ 

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10~----------~----------+---------~ 

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0 10 20 30 

LENGTH, IN MILLIMETERS 

FIGURE B.-Comparison of length versus width of pedicle 

valves of Dawsonelloides canadensis (Billings, 1874). 

Lower sandstone of Tarratine Formation, USGC loc. 

2701-SD, Brassua Lake quadrangle, Somerset County, 

Maine. 

Occurrence.-USGS locs. 2701-SD, 2710-SD, 

2711-SD, 2705-SD, 2704-SD, 2699-SD, 2703-SD, 

2708-SD, 2861-SD, 2872-SD, 2743-SD, 2725-SD, 

2801-SD, 2696-SD, 2700-SD, 2860-SD, 2847-SD, 

2812-SD, 2766-SD, 2813-SD, 27 40-SD, 2776-SD, 

3486-SD, 2857-SD, 3090-SD, 2849-SD, 3089-SD, 

2770-SD, 2767-SD, 2777-SD, 2797-SD, 2783-SD, 

2803-SD, 2799-SD, 2807-SD, 2771-SD, 2802-SD, 

2830-SD, 3482-SD, 2890-SD, 2706-SD, 3476-SD, 

Piseataquis and Somerset Counties, Maine. 

Stratigraphic loc.ation.-Seboomook Formation 

(Lower Devonian), and sandstones of the Tarratine 

Formation. 

Figured specimens.-USNM 126250, 126245, 

126253, 126239, 126251, 126244, 126252, 126246, 

126233. 

Unfigured specimens.-USNM 126249. 

Measured specimens.-VSNM 126705. 

Genus EODEVONARIA Breger, 1906 

Eodevonaria arcuata (Hall, 1857) 

Plate 11, figures 8-16 

Eodevonaria arcuata (Hall, 1857), see Boucot and Harper, 

1968, p. 153-156, pl. 27, figs. 1-7. 

Exterior.-The pedicle valve is highly convex and 

the brachial valve is gently concave. Body cavity narrow. Hinge line straight, maximum width loeated at 

hinge line. Shell outline subcircular to elliptical (deformation has changed outline of many specimens) . 

Ears flattened. Pedicle valve interarea orthocline to 

gently apsacline, brachial valve interarea hypercline. 

Delthyrium completely closed by convex pseudodeltidium, notothyrium closed by convex chilidium. Pedicle valve interarea about three times as long as that 

of brachial valve. Anterior margin rectimarginate. 

Spines originate at base of pedicle valve interarea, 

but very rare and seldom observed. Hinge line denticulation visible at junction of two interareas. Costellae originate largely by bifurcation. Costellae undulate gently, do not increase in width anteriorly. 

Costellae low, rounded in cross section, separated by 

inters paces of similar form. Number of spines along 

posterior margin of pedicle valve has not been observed to exceed eight. 

Pedicle valve interior.-Two stubby, laterally direeted hinge teeth situated anterior of delthyrial 

cavity and hinge line, just bordering edges of delthyrium. Low median septum extends from delthyrial cavity to about midlength. Hollow spine bases 

rarely seen along junction of interarea and bottom of 

valve. Two posterolateral ridges diverge from midline and interlock with corresponding anterolaterally 

dh~ected posrterior ridges of brachial valve. Interior 

of ears pustulose, remainder of interior bears impress of external ornamentation in addition to being 

pustulose. Muscle field very weakly impressed, consists of two pairs of elongate impressions paralleling 

median septum, plus small pair posteriorly located, 

oval imp·ressions. 

Brachial valve interior.-Fused, prostrate, pos.-

teriorly directed cardinal process lobes. Lateral to 

bas1e of cardinal proeess lobes are anterolaterally 

directed socket ridges. Low platform of secondary 

material, anterior of fused cardinalia, trifurcates 

anteriorly into median septum extending to midlength and into two anderidia. which enclose muscle 

field. Near anterior portion of median septum ma.y 

be developed pair of accessory septa.. Valve interior 

pustulose posteriorly, peripherally crenulated by impress of external ornamentation. Muscle field con-
28 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

si•Sits of paired, elongate adductor impressions which 

parallel median septum. 

Measurements.-The relationship between length 

and width of pedicle valves is essentially random 

with a high degree of dispersion (fig. 9). This condition reflects. the fact that the specimens were selected from a very small size range and that they 

have been subjected to a high degree of mechanical 

deformation. 

20 

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WIDTH, IN MILLIMETERS 

FIGURE 9.-Comparison of length versus 

width of pedicle valves of Eodevonaria 

arcuata (Hall, 1857). Tomhegan Formation, USGS loc. 2820-SD, Brassua 

Lakie quadrangle, Somerset County, 

Maine. 

Occurrence.-VSGS lociS. 2820-SD, 2750-SD, 

2852-SD, 2814-SD, 2839-SD, 2873-SD, 2840-SD, 

Brassua Lake quadrangle, Somerset County, Maine. 

Stratigraphic loca.tion.-T'omhegan Formation. 

Distribution.-Eastern North America. 

Figured specimens.-VSNM 126230, 126234, 

126235, 126232, 126238, 126226. 

Unfigured specimens.-VSNM 126224. 

Measured specimens.-126677 A-126677 AN. 

Subfamily CHONOSTROPHIELLINAE 

Genus CHONOSTROPHIELLA Boucot and Amsden, 1964 

Chonostrophiella complanata (Hall, 1857) 

Plate 11, figures 17-25; plate 12, figures 1, 2 

Chonostrophiella complanata (Hall, 1857), see Boucot and 

Amsden, 1964, p. 881-882, pl. 141, figs. 1-11. 

Exterior.-Pedicle valve flat or gently concave except in strongly concave peripheral region. Brachial 

valve gently convex. Maximum width located on 

straight hinge line. Pedicle valve interarea catacline 

to steeply apsacline, brachial valve interarea steeply 

ana'Cline. Pedicle valve interarea relatively long, 

brachial valve interarea relative·ly short. Delthyrium 

usually open, includes angle of about 90° except in 

few specimens that have a small pseudodeltidium 

located apically. Notothyrium modified laterally by 

small chilidial plates which extend medially almost 

to midline but have not been observed in conjunct 

state. Fine, radial costellae originate by both bifurcation and implantation, crossed by closely spaced 

concentric ornamentation that results in granulose 

effect. Shell outline transversely elliptical. Posterior 

part of lateral margin straight but anterior part and 

anterior margin gently rounded. Anterior commissure rectimarginate. Base of pedicle valve interarea 

bears short spines (three to seven on each side of 

midline). 

Pedicle valve interior.-Very short dental lamellae 

support spatulate hinge teeth. Dental lamellae diverge at angle between about 90° and 120°. Dental 

lamellae enclose posterior part of poorly impressed 

muscle field. Muscle impressions posterolaterally 

delineated by bounding ridges which extend from 

base of dental lamellae. Diductors compose bulk of 

muscle field; adductor impressions scarcely recognizable, restricted to posterior part of muscle field. 

Adductor impressions elongate, situated jus•t anterior of delthyrial cavity. Mus.cle field divided meddally 

by anteriorly bladelike septum with triangular cross 

section posteriorly. Median septum extends anteriorly to about midlength, muscle field about half as 

wide as maximum width. Hollow spine bases originate at base of palintrop.e, extend medially until 

reaching exterior where they diverge laterally. Region posterolateral to musde field pustulos~. External ornamentation impression present peripherally. 

Brachia-l valve interior.-Cardinal process lobes, 

stria,te both posteriorly and medially, bounded posteriorly by chilidial plates, anrteriorly fused with 

buttres1s plates. Muscle impressions consist of two 

pairs of adductors, one posterolateral and other anteromedial in posi·tion, separated from each other by 

low, trifid, platform of secondary material. Dental 

sockets not crenulated, laterally directed, bounded 

by interarea and short socket ridges. Costellae impressed on interior, become more pronounced peripherally. Muscle field restrioted to posterior quaner of 

valve. 

Measurements.-Relation between length and 

width of pedicle valves is linear with a relatively low 

degree of dispersion (fig. 10). 

Comparison.-C. dawsoni may be junior synonym 

of C. complanata but adequate material of former is 

not available for comparison. Adequate comparative 

material of other species of Chonostrophiella is not 

available. 

Occurrence.-USGS locs. 2718-SD, 2720-SD, 
SYSTEMATIC PALEONTOLOGY 29 

30~----------~----------,-----------,---------~ 

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a: 

w 

1- 20 w 

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::£ 

1- .. t? 10 z 

w 

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10 20 30 40 

WIDTH, IN MILLIMETERS 

FIGURE 10.-Comparison of length versus width of pedicle valves of Ckonostropkiella c,omplanata (Hall, 1857) . Lower .sandstone of Tarratine 

Formation, USGS loc. 2718-SD, Long Pond quadrangle, Somerset County, 

Maine. 

2767-SD, 2719-SD, 2691-SD, 2721-SD, 2722-SD, 

3090-SD, 2796-SD, 2727-SD, 2777-SD, 2766-SD, 

3088-SD, 2824-SD, 2862-SD, 3482-SD, 2783-SD, 

2861-SD, 2890-SD, Somerset and Piscataquis Counties, Maine. 

Stratigraphic location.--Seboomook Formation 

(Lower Devonian), and upper and lower sandstones 

of the Tarratine Formation (Lower Devonian). 

Distribution.-Eastern North America. 

Figured specimens.-USNM 126254, 126237, 

126240,126241,126236,126225,126243,126242. 

Suborder RHYNCHONELLOIDEA 

Superfamily RHYNCHONELLACEA 

Family TRIGONIRHYNCHIIDAE 

Genus CUPULAROSTRUM Sartenaer, 1961 

Cupularostrum macrocosta Boucot, n. sp. 

Plate 12, figures 3-11 

Exterior.-Unequally biconvex shells with brachial valve having greater convexity. Cardinal margin 

terebratulid, pedicle foramen submesothyrid in position. Hinge line very short, curved in anterolateral 

direction. Deltidial plates conjunct. Anterior commissure uniplicate, strongly crenulate. Pedicle valve 

beak straight. Moderately sized ribs with four to 

five in sulcus of pedicle valve, seven to nine on 

either flank. Brachial valve bears eight to ten ribs 

either side of median line. Shell outline pentagonal 

to subcircular with greatest width at about midlength. Lateral margins rounded, anterior margin 

greatly rounded. Shells large, many reaching length 

of 3 em. 

Pedicle valve interior.-Dentallamellae short, support short, bladelike, laterally directed hinge teeth. 

Muscle field impression barely discernible except in 

large specimens. Paired diductor scars enclose median, diamond-shaped adductor scar which narrows 

anteriorly at about one-third distance to anterior 

margin. Well-developed pedicle callist located at rear 

of delthyrial cavity. Muscle area no more than onethird of maximum width, commonly somewhat less. 

Interior strongly plicated by impress of external 

ornamentation. 

Brachial valve interior.-Discrete hinge plates 

slightly overlap lateral sides of small septalium, latter supported by median septum which extends anteriorly about one-half length of valve. Laterally 

directed dental sockets crenulated by about seven to 

ten ridges distinctly impressed on anterior and bottom of sockets. M u~cle field not distinctly impressed. 

Interior strongly plicated by impress of external 

ornamentation. 

Comparison.-Externally C. macrocosta resembles 

Billings' (1874) "Rhynchonella" excellens and uR." 

dryope, both from Gaspe limestone No. 3. uR." dryope has only three costae in sulcus, whereas "R." 

excellens has much finer costae than C. macrocosta. 
30 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

C. macrocosta · reaches much larger size than the 

typ·e species C. recticostatum Sartenaer, 1961, which 

only has three and sometimes four costae in sulcus. 

Discussion.-Hall and Clarke's ( 1894) definition 

of this genus (as Camarotoechia) make8 necessary 

a complete acquaintance with the structure of cardinalia before a species can be generically assigned. 

External form and ornamentation are not diagnostic ; true Cupularostrum has septalium commonly 

roofed over by a perforate hinge plate, also crenulate 

dental sockets. 

Occurrence.-VSGS locs. 2750-SD, 2814-SD, 

2852--SD, 2820-SD, 28'40-SD, 2842-SD, Brassua 

Lake quadrangle, Somerset County, Maine. 

Stratigraphic location.-Tomhegan Formation 

(Lower Devonian) . 

H olotype.-VSNM 125851. 

Figured specimens.-VSNM 125852, 125855, 

125857, 125904. 

Cupularostrum 7 sp. 

Plate 12, figures 12-21 

Exterior.-Vnequally biconvex shells, brachial 

valve having greater convexity. Shell outline subcircular, greatest width near midlength. Cardinal 

margins terebratulid, beak suberect. Hinge line very 

short, curved in anterolateral direction. Anterior 

commissure unip.Jicate, crenulate. Brachial valve 

bears well-developed fold, pedicle valve has corresponding sulcus. Costae, about three in sulcus, four 

on fold, five on each flank. 

Brachial valve interior.-Serial sections show septalium covered with hinge plate anterior of small 

apical foramen. Median septum supports sep•talium. 

Interior strongly plicated by external ornamentation. Nature of dental sockets not elucidated by 

serial sections. 

Pedicle valve interior.-Small dental lamellae 

situated either side weakly impressed muscle field 

which is situated in delthyrial cavity. Interior 

strongly plicated by impress of external ornamentation. 

Occurrence.-VSGS loc. 3601-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian) . 1

Figured specimens.-VSNM 125862, 125859. 

Unfigured specimens.-VSNM 125860. 

Genus ANCILLOTOECHIA Havlicek, 1959 

Ancillotoechia sp. 

Plate 12, figures 22-26 

Discussion.-A few poorly preserved specimens 

from Maine ;possess external form and ornamentation of Ancillotoechia. The material is too poor to 

be specifically assigned. During the study of Early 

Devonian rhynchonellida from Maine, here assigned 

to Ancillotoechia, the close similarity of external 

footures of the rhynchonellid species bidentata Hisinger, bialvea~a Hall, and acinum Hall was investigated. Hall ( 1863, p. 215) drew attention to these 

similarities by comparing the thTee species. Serial 

sectioning of Amsden's species Ancillotoechia haraganensis (close to and possibly synonymous with A. 

bialveata (Hall)), uRhynchonel'la/' bidentata, and 

uR." acinus shows that haraganensis belongs to 

Ancillotoechia (fig. 11) ; that bidentata belongs to an 

undescribed homeomorphic genus (fig. 13); and 

that acinus belongs to Diabolirhynchia Drot, 1964 

(fig. 12). 

Occurence.-VSGS loc. 3499-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian) . 

Figured specimen.-VSNM 125902. 

Unfigured specimen.-VSNM 125901. 

"Ancillotoechia" d. "A." altisulcata (Amsden, 1951) 

Plate 12, figures 27-31 

Exterior.-Vnequally biconvex shells having 

gently convex pedicle valve, subpyramidal brachial 

valve. Brachial valve highly convex, made subpyramidal by fold Wihich extends upwards from rest of 

valve, near midlength, at angle of a;bout 30°. Pedicle 

valve has broad, low sulcus and very high tongue 

13.4 

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12.9 

13.3 

FIGURE 11.-Serial sections of three specimens of A ncillotoechia haraganensis (Amsden) USNM 125858, X 4.5. 

Haragan Shale, White Mound, 3 miles west of Nebo, Okla. 

Numbers are measurements in millimeters from posterior 

end of shell. 
SYSTEMATIC PALEONTOLOGY 31 

Q @> 

10.65 

9.75 

10.4 

9.85 

10.1 

cf!Jo 

10.2 (9 

10.0 

9.7 

9.8 

FIGURE 12.-Serial sections of Diabolirhynchia acinus (Hall, 1863), X 4.5, USNM 

126049. Waldron Shale, Waldron, Indiana. Numbers are measurements in millimeters from posterior end of shell. 

anteriorly corre·sponding to high fold in brachial 

valve. Shells pentagonal in outline, greatest width 

near midlength. Lateral margins rounded into very 

gently rounded anterior margin. Anterior margin 

uniplicate, strongly crenulate. Pedicle valve beak 

incurved, terebratulid. Fold bears about four angular costae, sulcus contains about three. Each flank 

bears about seven costae. Neither fold nor sulcus 

developed in umbonal regions of shell. Concentric 

growth lines present on valves. 

Pedicle valve interior.-Serial sections (fig. 14) 

show valve possesses short dental lamellae bordering delthyrial cavity and muscle fields poorly impressed. 

Brachial valve interior.-Septalium formed by 

median septum that bifurcates into latterally diverging branches posteriorly. Borders of septalium overlapped by discrete hinge plates. Dental sockets 

roofed over posteriorly by outer edges of hinge 

plates. Muscle field poorly impressed. 

Occurrence.-USGS loc. 3488-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian). 

Figured specimens.-USNM 125854. 

Family UNCINULIDAE 

Genus SPHAERIRHYNCHIA Cooper and Muir-Wood, 1951 

Spbaerirbyncbia sp. 1 

Plate 12, figures 32-36; plate 13, figures 26-28 

Exterior.-Unequally biconvex shells with brachial valve about twice convexity of pedicle valve. 

Shell outline subcircular to longitudinally elliptical. 

Anterior and lateral margins rounded, greatest 

width near midlength. Brachial valve bears broad, 

low fold, pedicle valve corresponding suleus. Pedicle 

valve has long tongue anteriorly which extends up 

to join fold on brachial valve. Anterior margin uniplicate, crenulate. Cardinal margin terebratulid in 

form, beak of pedicle valve appears incurved. Small, 

rounded costae, about ten costae in fold and sulcus, 

about ten costae each flank. 

Pedicle valve interior .-Short dental lamellae located either side of delthyrial cavity. Se,rial sections 

indicate muscle field not very deeply impressed. 
32 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

9.55 

8.95 

8.75 

9.4 

9.3 

0 8.9 

8.7 

9.2 

9.1 8.8 8.6 

FIGURE 13.-Serial sections of uRhync.honella" bidentata 

(Risinger, 1826), X 4.5, USNM 125880. Silurian beds 

near Klinteham, Gotland, Sweden. Numbers are measurements in millimeters from posterior end of beak. 

Brachial valve interior.-Septalium supported by 

median septum. Discrete hinge plates projeot over 

medial edge of cruralium. Lateral ed~ges of hinge 

plates project over medial edge of dental sockets. 

Comparison.-Maine material is too scanty for 

specific identification. 

Occurrence.-USGS loc. 3470-SD, 3469-SD, 

Spencer Lake quadrangle, locality 5586-SD, Attean 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian). 

Figured specimens.-USNM 125874, 160127-

160129. 

Unfigured specimens.-USNM 125875, 126385. 

Sphaerirhynchia sp. 2 

Plate 13, figures 1-6 

Exterior.-Unequally biconvex shells with brachial valve having greater degree convexity. Shell 

outline longitudinally elliptical, maximum width located about two-thirds the distance to anterior margin. Beaks attenuated, pedicle valve incurved. Pedicle valve cardinal margin terebratulid in form. 

Brachial va.lve bears low fold, pedicle valve corresponding sulcus. Anterior commissure uniplicate, 

crenulate. Relatively coarse, rounded costae, two on 

fold in small specimens to six in large specimens. 

10.25 10.3 

10.2 10.15 

10.7 10.5 

FIGURE 14.-Serial sections of "Ancillotoechia" cf. "A." 

altisulcata (Amsden, 1951), parallel to hinge line distance 

from beak given in millimeters; X 4.5. Hardwood Mountain Formation, USGS loc. 3488-SD, Spencer Lake quadrangle, Somerset County, Maine. 
SYSTEMATIC PALEONTOLOGY 33 

Sulcus of small specimens contains one costa, flanks 

bear from six to eight costae each. Lateral and anterior margins rounded. Radial ornamentation 

crossed by concentric growth lines. 

Pedicle valve.-Serial sections of pedicle valve 

show presence of shovt dental lamellae bounding 

delthyrial cavity. They are partly obsolete due to 

deposition of secondary material in umbonal cavities. 

Muscle field very deeply impressed into secondary 

material deposited in posterior portion of shell. 

Brachial valve interior.-Posteriorly located, small 

septalium supported by long median septum extends 

to about midlength. Interior of valve strongly plicated by impress of costae except in umbonal region. 

Comparison.-S. sp. 2 has much coarser costae 

than S. sp. 1 and resembles S. sp. 3 in this regard. 

S. sp. 2 has a more deeply impressed pedicle valve 

muscle field than S. sp. 3. Not enough material of 

any of these forms is available for sound specific 

identification. 

Occurrence.-USGS loc. 3499-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigra.phic location.-Beck Pond Limestone 

(Lower Devonian) . 

Figured specimens.-USNM 125877, 125876. 

Unfigured specimens.-USNM 125878, 125879, 

126389. 

Sphaerirhynchia sp. 3 

Plate 13, figures 7-12 

Exterior.-Unequally biconvex shells, brachial 

valve having a;bout one and one-half times convexity 

of pedicle valve. Valve outline subcircular, greatest 

width near midlength. Anterior and lateral margins 

rounded. Brachial valve bears low, broad fold, pedicle valve corresponding sulcus. Pedicle valve beak 

incurved, cardinal margins terebratulid in form. 

Anterior commissure uniplicate, crenulate. Low, 

rounded costae with about six on fold, five in sulcus, 

about ten to twelve each flank. 

Pedicle valve interior.-Dental lamellae very 

short, almost entirely obsolete due to deposition of 

secondary material in umbonal cavities. Muscle field 

extends about one-third distance to anterior margin, 

very elongate in form. Well-developed pedicle callist 

located at posterior of delthyrial cavity. Anterior of 

pedicle callist a pair of very narrow anterolaterally 

striated diductor impressions. Lateral to medial diductor impression pair roughened, elongate impressions which may have served as site for pair of 

lateral diductors. Peripherial parts of valve plicated 

by impress of external ornamentation. 

Brachial valve interior .-Serial sections, show 

septalium supported by long median septum. 

Occurrence.-USGS loc. 3601-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian). 

Figured specimens.-USNM 125870, 125871. 

Sphaerirhynchia 1 sp. 

Plate 13, figures 13-18 

Exterior.-Unequally biconvex shells, brachial 

valve about twice convexity of pedicle valve. Specimen outline transversely elliptical although so deformed that it is difficult to be sure of original form. 

Maximum width located near midlength. Pedicle 

valve bears low, broad fold, pedicle valve corresponding sulcus. Lateral and anterior margins rounded. 

Anterior commissure uniplica:te, crenulate. Fold 

bears about four to five low, rounded costae, sulcus 

contains about three to four costae. Costae in tongue 

of pedicle valve medially grooved. Each flank bears 

about 17 costae. 

Pedicle valve interior.-Dental lamellae very 

short, obsolete due to deposition of secondary material in umbonal cavities. Pedicle callist deeply impressed, occupies posterior part delthyrial cavity. 

Diductor impressions deeply impres:sed, abut anterior face pedicle callist. Diductors very narrow, 

medially separated by low myophragm, extend anteriorly about one-third length of valve. Impression 

of costae noticeable in peripheral region of valve, 

absent posteromedially where overlain by s·econdary 

material. 

Brachial valve interior.-Small, posteriorly located septalium supported by median septum that 

extends anteriorly about one-third length of valve. 

Septalium part roofed over by conjunct hinge plates 

as in Cupularostrum. Dental sockets medially roofed 

over by projecting edges of hinge plates. Species is 

similar to Sphaerirhynchia except as regards conjunct hinge plates; form very unlike Cupularostrum 

which does not approach almost globular shape of 

these shells. 

Occurrence.-USGS loc. 3488-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian). 

Figured specimens.-USNM 127385A, B. 

Family UNCERTAIN 

Genus SULCA TINA Schmidt, 1964 

Sulcatina sp. 

Plate 13, figures 19-25 

Exterior.-Unequally biconvex shells with brachial valve about 11;2 times convexity of pedicle valve. 

Greatest width about three-quarters of distance to 

anterior margin. Shell outline transversely elliptical. 
34 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

Pedicle valve beak strongly incurved, margin terebratulid in form. Lateral margins strongly rounded, 

anterior margin gently rounded. Brachial valve has 

pronounced broad fold which bears about five to six 

rounded costae. Pedicle valve has corresponding sulcus which commonly contains about four or five 

cos.tae. Flanks each bear about nine to eleven costae. 

Anterior commissure uniplicate, crenulate. On s·pecimens studied cos.tae broaden anteriorly, not observed to bifurcate or increase by implantation. 

Hinge line very short, curved in anterolateral direction. Brachial valve beak completely concealed beneath incurved pedicle valve beak. 

Pedicle valve interior.-Dental lamellae very 

short, almost entirely obsolete in large specimens 

owing to deposition of secondary material in urnbona} cavities. They support s·tout, plate-like hinge 

teeth which project beyond relatively short hinge 

line. Crural fossettes relatively narrow, laterally 

directed, bordered by hinge line and hinge teeth. 

Muscle field deeply impressed, consists of subciroular diductor impression, medially divided by low 

myophragm, which anteriorly and laterally surrounds small, posteriorly located, elongate adductor 

impres.sions. Behind myophragm, anterior or prominent pedicle callist which occupies posterior wall 

and base of delrthyrial cavity, are two pairs of 

elongate adjustor impressions. Area lateral to muscle 

field somewhat roughened by deposits of secondary 

material, and muscle field itself surrounded by low 

ridge secondary material which begins at base of 

dental lamellae and continues in anterior and then 

'anterom·edial d-irection before becoming very faint 

in front of myophragm. 

Brachial valve interior.-Bifid cardinal process 

whose lobes curve to form scoop-shaped structure. 

Anterior part of structure nearly vertical but posteriorly swing medially and become inclined before 

joining near midline. Lateral faces of lobes have 

steps which parallel bottom of elongate, anterolaterally directed dental sockets which are roofed 

medially by projecting cardinal process lobes. N otothyrial cavity, between cardinal process lobes, has 

secondary material laid down anteriorly forming 

lozenge-shaped outline. Anterior of notothyrial cavity is low, sharp myophragm or ridge which extends 

about one-half length of valve. On either side of 

cardinalia and slightly anterior are deeply impressed, 

subcircular impressions of posterior adductor scars. 

Anterior of posterior adductor scars are elongate, 

paired anterior adductor impressions which extend 

to about midlength. 

Comparison.-S. sulcata (Cooper, 1942) has more 

costae on the fold and sulcus than does the material 

from Maine. S. tennesseensis (Foerste) has about 

the same number of costae but is more subcircular 

in outline than the Maine material; as Tennessee 

specimens are smaller; they may be an earlier 

growth stage of the Maine material. Adequate comparative specimens are not available to specifically 

identify the Maine material. 

Occurrence.-USGS loc. 3488-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian). 

Figured specimens.-USNM 125850, 125853A, 

125847, 125848. 

Unfigured specimens.-USNM 125849, 126388. 

Family EATONIIDAE 

Genua COSTELLIROSTRA Cooper, 1942 

Costellirostra sp. 

Plate 14, figures 1-5 

Exterior.-Unequally biconvex shells with brachial valve having greatest convexity. Brachial valve 

develops relatively narrow fold anterior of midlength. Fold rises abruptly at angle of about 30° 

from rapidly descending anterior part of valve. 

Pedicle valve bears relatively shallow sulcus corresponding to fold, anterior part of pedicle valve prolonged into a tongue. Specimen outline subtriangular 

due to attenuated beak. Greatest width slightly anterior of midlength. Lateral and anterior margins 

rounded. Pedicle valve beak incurved, cardinal margins terebratulid in form. Relatively low, fine striae 

barely visible on Maine material. 

Pedicle valve interior.-lmperfe·ctly preserved 

pedicle valve interior shows pair deeply impressed 

adductor impressions, small in size, sunk into pit 

near anterior part of muscle field. 

Brachial valve interior.-Median septum extends 

to about midlength on Maine material, nature of 

cardinalia not established. 

Comparison.-External form and ornamentation, 

coupled with the nature of the muscle field in the 

pedicle valve, justify assignment to Costellirostra, 

but specific identification is not possible. 

Occurrence.-USGS loc. 2806-SD, Pierce Pond 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-McKenney Ponds Member of the Tarratine Formation (Lower Devonian). 

Figured specimen.-USNM 125885. 

Unfigured specimens.-USNM 125884, 125886. 

Genua EATONIA Hall, 1857 

Eatonia cf. E. medialis (Vanuxem, 1842) 

Plate 14, figures 6-13 

Exterior.-Unequally biconvex shells with brachial valve very inflated, pedicle valve gently convex. 
SYSTEMATIC PALEONTOLOGY 35 

Brachial valve bears prominent fold which originates 

just anterior of umbo and rises at angle of about 

30° from descending anterior part of valve. Shell 

outline transversely elliptical, greatest width near 

midlength. Pedicle valve beak incurved, hinge line 

curved anterolaterally. Rounded costae, four on fold, 

three in sulcus, and six on each flank. Lateral margins rounded, but anterior margin almost straight. 

Anterior part of sulcus projects up as prominent 

tongue to engage fold of brachial valve. Anterior 

commisure uniplicate, crenulate. 

Pedicle valve interior.-Dental lamellae not observed on Maine specimens, but deeply impressed 

muscle field present. Muscle field consists of paired 

diductor impressions, surrounded by narrow ridge 

of secondary material which originates near sides 

of delthyrial cavity, enclosing pair of small, elongate, 

medially divided adductor impressions sunk below 

level of diductor impressions. Low narrow median 

septum traverses muscle field, reaches to about midlength. Impression of external costae marked in 

peripheral regions of valve. 

Brachial valve interior.-Mass.ive, terminally bifid, posteriorly located cardinal process supported by 

long narrow median septum which reaches almost 

to midlength. Brachiophores appear to be slender 

and diverge· anterolaterally from base of cardinal 

process. Muscle field divided by median septum and 

consists of two pairs adductor impressions, posterior 

pair small and subcircular in outline, anterior pair 

elongate and extending to about midlength. Muscle 

impressions separated by low rounded ridge of secondary material about normal to median septum. 

Comparison.-Maine specimens resemble E. medialis, but their poor state of .preservation precludes 

specific identification. 

Occurrence.-USGS loc. 3499-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian). 

Figured specimens.-USNM 125872, 125873, 

125882B. 

Unfigured specimens.-USNM 126387. 

Eatoni• 'l sp. 

Discussion.-A few poorly preserved specimens 

from Parker Bog Formation have prominent fold 

and sulcus with Eatonia tYJPe costae. Nothing is 

known of the interior of this material ; exterior is 

so poorly preserved that assignment to Eatonia can 

only be specul~ative. 

Occurrence.-USGS loc. 3477-SD, Pierce Pond 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Parker Bog Formation 

(Lower Devonian) . 

Unfigured specimens.-USNM 126388. 

Family RHYNCHOTREMA TIDAE 

Genus MACHAERARIA Cooper, 1955 

Machaeraria mainensis Boucot, n. sp. 

Plate 14, figures 14-21 

Exterior.-Unequally biconvex shells with brachial valve having about 11;2 times convexity of pedicle 

valve. Shell outline transversely elliptical with greatest width near midlength. Brachial valve bears relatively broad low fold which originates near umbo; 

pedicle valve has corresponding sulcus. Pedicle valve 

beak slightly incurved, hides beak of brachial valve. 

Cardinal margins subterebratulid. Pedicle valve foramen submegathyrid, deltidial plates appear to be 

apically conjunct. Lateral and anterior margins 

rounded. Pedicle valve sulcus prolonged into tongue 

which fits against fold of brachial valve. Angular 

costellae about four on fold, three in sulcus, about 

eight each flank. Anterior commissure uniplicate, 

crenulate. 

Pedicle valve interior.-Short dental lamellae support relatively stubby hinge teeth. Dental lamellae 

almost obsolete due to deposition of secondary material in umbonal cavities. Muscle field well impressed, consists of elongate diductor impression 

medially divided by low myophragm and surrounding a pit which contains small, elongate adductor 

impressions. Periphery crenulated by impression of 

external costellae, but remainder of interior relatively smooth due to deposition of secondary material. 

Brachial valve interior.-Linear cardinal process 

anteriorly joined by low, rounded myophragm or 

ridge which extends to about midlength of valve. 

Laterally flanking cardinal process are relatively 

stubby hinge plates supported by crural plates. Nature of brachiophores not determined on Maine material. Muscle field quadripartite, consists of pair 

medial adductor impressions which are elongate in 

outline and extend to about midlength from just 

anterior of cardinalia. Lateral pair adductor impressions subtriangular in outline, located just anterior 

of crural plates. Dental sockets relatively shallow, 

laterally directed. Base each crural plate medially 

directed to meet myophragm, and form sessile cruralium. 

Comparison.-M. mainensis lacks flaring margins 

of sulcus as developed in Early Devonian type species M. formosa. 

Occurrence.-USGS locs. 3479-SD, 2712-SD, 

Spencer Lake quadrangle, Somerset County, Maine. 
86 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

Stratigraphic location.-Base of Hobbstown Formation (Upper Silurian). 

Holotype.-USNM 125869. 

Figured specimens.-USNM 125867 A, 125868, 

125869A. 

Unfigured specimens.-USNM 126376, 126377. 

Suborder ATRYPOIDEA 

Superfamily A TRYPACEA 

Family ATRYPIDAE 

Subfamily A TRYPINAE 

Genua ATRYPA Dalman, 1828 

Atrypa cf. A. tenneaseenais Amsden, 1949 

Plate 14, figures 22-27 

Exterior.-Subsequently biconvex shells, brachial 

valve slightly more convex than pedicle valve. Valve 

outline variably transverse to elongate, but deformation mh..r have partly determined outline because 

most specimens are more or less crushed. Straight 

hinge line, shorter than greatest width near midlength. Anterior commissure rectimarginate, crenulate. Cardinal margin submegathyrid, delthyrium 

appears unmodified. Pedicle valve beak probably incurved over that of brachial valve. Radially disposed 

costae crossed by very prominent concentric lamellae, free at anterior ends as frills. Brachial valve 

bears about four unbranched costae on each side of 

median costa while pedicle valve bears five unbranched costae each side of midline. No specimen 

exceeds about 1 em length. Lateral and anterior margins rounded. 

Pedicle valve interior.-Very short dental lamellae 

on either side of delthyrial cavity support stout 

hinge teeth which project vertically and have subcircular cross section. Muscle field poorly impressed, 

appears flabellate, extends anteriorly to near midlength, about half as wide as valve. 

Posteriorly located, elongate pair of adductor impressions anteriorly and laterally surrounded by 

flabellate diductor impressions. Costae impression 

marked on interior of valve except in posteromedial 

parts. 

Brachial valve interior.-Pair of discrete hinge 

plates diverge laterally from midline and form anterior socket walls. Crenulations barely discernible 

in bottom of dental sockets. Low myophragm extends anteriorly from notothyrial cavity to position 

one-third of distance from posterior margin. Muscle 

field very weakly impressed. Costae impression 

marked except in posteromedial parts of valve. 

Comparison.-Maine specimens resemble small 

specimen:s of Atrypa tennesseensis in external form 

and ornamentation. Secondary costae arP not present 

except in anteriormost parts of the Maine specimens, 

whereas in larger specimens from Oklahoma (Amsden, 1951, pl. 17, fig. 33) numerous, well-defined 

costae originate by bifurcation in peripheral regions 

of shell. Amsden's figure 32 is a specimen with 

anomalous ornamentation consisting of costae which 

are much stronger and bifurcate near umbo and may 

not belong to A. tennesseensis. 

Occurrence.-USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Base of Hobbstown Formation (Upper Silurian). 

Figured specimens.-USNM 126002-126004. 

U nfigured specimens.-USNM 126396-126401. 

Atrypa cf. A. arctostriata Foerste, 1903 

Plate 14, figures 28-29 

Exterior.-Subequally biconvex shells with brachial valve having somewhat greater degree of convexity than pedicle valve. Shell outline subcircular, 

greatest width near midlength. Anterior commissure rectimarginate, crenulate. Lateral and anterior 

margins rounded. Frill of spines surrounds periphery, costellae increase by bifurcation and are crossed 

by concentric lamellae having free frills. 

Pedicle valve interior.-Only one fragm.entary 

pedicle valve is available, but it indicates that in 

small shells the muscle field is weakly impressed, 

flabellate in form, posteriorly bounded by short 

dental lamellae. 

Brachial valve interior.-Discrete hinge plates anteriorly bound dental sockets. Hinge plates and 

dental sockets anterolaterally directed. Short myophragm medially divides weakly impressed, posterior, elongate adductor impressions, posteriorly stops 

at undivided notothyrial cavity, which is probably 

the site for diductor attachment. Dental sockets very 

feebly crenulated basally. Anterior of posterior pair 

of adductor impressions is peripheral impress of 

external ornamentation. 

Comparison.-The Maine material is of the same 

external form and ornamentation as Atrypa arctostriata, but is too poorly preserved to be specifically 

assigned without doubt. 

Occurrence.-USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Base of Hobbstown Formation (Upper Silurian). 

Figured specimens.-USNM 126014A, 126015B. 

Atrypa "reticularis" (Linnaeus, 1767} 

Plate 15, figures 1-6 

Atrypa "reticularis" (Linnaeus, 1767), see Boucot, 1959b, 

p. 741-742, pl. 91, figs. 7-9. 

Exterior.-Unequally biconvex shells, brachial 

valve about twice convexity of pedicle valve. Hinge 

line about two-thirds as wide as maximum width ' which is at about one-third of distance to anterior 
SYSTEMATIC PALEONTOLOGY 37 

m.argin. Cardinal margins submegathyrid. Delthyrium open, apparently unmodified. Pedicle valve 

weakly sulcate. Anterior commissure weakly uniplicate, crenulate. Shells longitudinally elongate to subcircular with rounded anterior and lateral margins. 

Costellae increase by bifurcation, crossed by concentric growth lines. Pedicle valve beak straight to 

gently incurved. 

Pedicle valve interior.-Stout, bla.delike hinge 

teeth project anteromedially from rear of valve, supported by short dental lamellae which are almost 

entirely obsolete due to deposition of secondary material in umbonal cavities. Muscle impressions large, 

flabellate, extends to about midlength, about twothirds as wide as valve. Muscle impressions elliptical 

pair small, posteriorly located adductor impressions 

laterally and anteriorly surrounded by deeply impressed diductor field. Diductor field radially divided 

into number of sectors by short myophragms which 

begin near anterior margins of delthyrial cavity. 

Deeply impressed horizontally striate pedicle callist 

located on posterior wall delthyrial cavity. Crural 

fossettes relatively deep, restricted to area lateral 

of hinge teeth. Valve periphery crenulated by impress of external ornamentation. Areas lateral to 

muscle impressions deeply pitted. 

Comparison.-Above description is based on specimens from the Tomhegan Formation whkh resemble 

A. reticularis s. I. in character of external form and 

ornamentation. Additional sp·ecimens of Atrypa cf. 

A. reticularis, in a poor state of preservation, have 

been obtained from other units. SomP from the 

Hardwood Mountain Formation are covered with 

spines and have a peripheral frill of spines. 

Occurrence.-USGS locs. 3485-SD. 3150-SD, 

3475-SD, 3496-SD, 3469-SD, 3499-SD, 2820-SD, 

2750-SD, 3488-SD, 2761-SD, 2840-SD, 2730-SD, 

Somerset and Piscataquis Counties, Maine. 

Stratigraphic location.-Tomhegan Formation 

(Lower Devonian), Seboomook Formation (Lower 

Devonian), Beck Pond Limestone (Lower Devonian), Hardwood Mountain Formation (Upper Silurian), hornfels on Limestone Hill (Lower Silurian), undifferentiated Silurian beds on Deer Island. 

'Figured specimens.-USNM 126008, 126010, 

126011, 126068. 

Unfigured specimens.-USNM 126390-126395. 

Family LISSATRYPIDAE 

Genus LISSATRYPA Twenhofel, 1914 

Lissatrypa sp. 

Plate 15, figures 7-16 

Exterior.-Unequally biconvex shells, pedicle 

valve about 11j2 times convex as relatively gently 

convex brachial valve. Valve outline subcircular, 

greatest width slightly posterior of midlength. Lateral and anterior margins evenly rounded. Anterior 

commissure rectimarginate. Pedicle valve delthyrium 

open, unmodified. Hinge line narrow, about one fifth 

as wide as greatest width of shell. Cardinal margins 

terebratulid. Pedicle valve beak suberect, tends to 

conceal brachial valve. Concentric growth lines. 

Pedicle valve interior.-Stout hinge teeth occur 

either side delthyrial cavity, laterally bound slightly 

raised pedicle callist on posterior wall delthyrial cavity. Muscle field deeply impressed, consists of narrow, median adductor impression on raised track 

and laterally bounded by elongate diductor impressions which extend to midlength and are medially 

bounded by anterolaterally trending, divergent 

ridges which originate at base of median adductor 

track. Valve interior smooth. 

Brachial valve interior.-Discrete, bulbous hinge 

plates medially join low, broad median septum which 

is triangular in cross section posteriorly and linear 

anteriorly. Muscle field two pairs elongate, posteriorly situated adductor impressions. Muscle field 

extends about one-third distance to anterior margin 

and is subcircular in outline. Spires atrypoid in 

nature, about three loops to each spire. 

Comparison.-The material is too poorly preserved to be specifically identified. The absence of a 

sulcus clearly indicates this material cannot be assigned to the genus Meifodia. 

Occurrence.-USGS locs. 3488-SD, 3473-SD, 

Spencer Lake quadrangle, locality 4843-SD, Attean 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian). 

Figured specimens.-USNM 125905A,B, 126000, 

125908A,B, 160130A,B. 

Unfigured specimens.-USNM 125906, 125909, 

126013. 

Genus NANOSPIRA Amsden, 1951 

Nanospira 1 sp. 

Plate 15, figure 16 

Exterior.-Brachial valve convex, bears prominent, broad sulcus originating near umbo. Maximum 

width located slightly anterior of curved hinge line. 

Lateral and anterior margins rounded. Anterior 

commissure sulcate. Exterior smooth except for concentric growth lines. 

Brachial valve intenor.-Pair of laterally directed 

hinge plates separated by median trough. Interior 

smooth. 

Comparison.-Single specimen from Maine has 

external form of N anospira but not enough evidence 

is availa~ble for generic assignment to be positive. 
38 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

Occurrence.-USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Base of Hobbstown Formation (Upper Silurian). 

Figured specimen.-USNM 126108A. 

Superfamily DA YIACEA 

Family LEPTOCOELIIDAE 

Genus LEPTOCOELlA Hall, 1859 

Leptocoelia ftabellites (Conrad, 1841) 

Plate 15, figures 17-24 

Leptocoelia flabellites (Conrad, 1841), s·ee Boucot, 1959b, p. 

741, pl. 91, figs, 1-6. 

Exterior.-Unequally convex shells with almost 

flat brachial valve, convex relatively naviculate pedicle valve. Greatest width near midlength. Lateral 

and anterior margins evenly rounded. Brachial valve 

bears low fold, originating near midlength of valve; 

pedicle valve has corresponding sulcus. Anterior 

margin uniplicate and strongly crenulate. Delthyrium open and unmodified. Pedicle valve beak 

suberect and incurved so as to conceal beak of 

brachial valve. Cardinal margins submegathyrid. 

Hinge line about two-thirds maximum width. Costae 

crossed by strong, concentric growth lines. Brachial 

valve fold bears two costae with four costae on each 

flank; sulcus of pedicle valve contains one costa with 

four to five on each flank. Costae increase in width 

anteriorly, do not bifurcate. Inters paces relatively 

broad, flat, costae evenly rounded. 

Pedicle valve interior.-Stout hinge teeth, having 

triangular cross section; lie on either side of delthyrial cavity. Anterior face crural fossette crenulated. Apex of triangular cross section of hinge tooth 

points anteriorly. Rear of delthyrial cavity occupied 

by pedicle callist located on slightly raised, striated 

pad of secondary material. Median face of each hinge 

tooth indented by step which parallels floor of valve 

and serves to articulate with distal part of brachiophore. Musde field flabellate in form, reaches anteriorly to about midlength, is from one-third to onehalf maximum width of valve. Muscle field consists 

of flabellate diductor impression, medially separated 

by low sharp myophragm which is most pronounced 

anteriorly. Diductor field encloses deeply impressed, 

small, elongate, paired adductor impressions which 

are longitudinally striate and partly roofed over 

posteriorly by projecting deposit of secondary material. Umbonal region of valve relatively smooth, 

remainder of valve strongly crenulated by impress 

of external ornamentation. 

Brachial valve interior.-Moundlike, terminally 

trifid cardinal process anteriorly joined by myophragm. Cardinal process laterally fused with socket 

plates. Crura bladelike, diverge anterolaterally. 

Dental sockets crenulated, roofed over medially by 

laterally inclined crura, anterolaterally rimmed by 

ridge of secondary material in large specimens. Myophragm extends to about midlength, narrow, low, 

and sharp anteriorly, becomes triangular in cross 

section and more massive posteriorly. Adductor 

field impression elongate in outline. In large specimens, median ridge of terminally trifid cardinal 

process rises above lateral ridges which are subdued by deposition of secondary material. 

Occurence. - USGS locs. 2691-SD-2705-SD, 

2707-SD, 2709-SD-2711-SD, 2717-SD-2722-SD, 

2725-SD-2727-SD, 2729-SD, 2731-SD-2735-SD, 

2737-SD, 2738-SD, 2740-SD, 2741-SD, 2743-SD, 

27 45-SD, 27 46-SD, 27 48-SD, 27 49-SD, 2751-SD, 

2760-SD, 2761-SD, 2765-SD-2771-SD, 2775-SD, 

2776-SD, 2778-SD-2790-SD, 2792-SD-2805-SD, 

2807-SD, 2808-SD, 2811-SD-2813-SD, 2819-SD, 

2821-SD, 2823-SD, 2824-SD, 2827-SD. 2829-SD, 

2830-SD, 2832-SD, 2834-SD, 2837-SD, ~843-SD2849-SD, 2853-SD, 2856-SD-2858-SD, 2860-SD, 

2862-SD, 2865-SD, 2870-SD, 2872-SD, 2877-SD, 

2879-SD, 2880-SD, 2882-SD, 2883-SD. 2890-SD, 

3089-SD-3092-SD, 3094-SD, 3225-SD-3229-SD, 

3471-SD, 3474-SD, 3481-SD, 3482-SD. 3486-SD, 

Somerset County; 2861-SD, 3088-SD, Piscataquis 

County, Maine. 

Stratigraphic location.-Misery Quartzite Member 

of the Tarratine Formation (Lower Devonian), upper and lower sandstones of the Tarratine Formation (Lower Devonian), Seboomook Formation 

(Lower Devonian), questionably in the Kineo Member of the Tomhegan Formation (Lower Devonian). 

Distribution.-This species is known from beds of 

late Helderberg to Schoharie age in eastern North 

America. 

Figured specimens.-USNM 126001, 126005, 

125907, 126009, 126012, 127387. 

U nfigured specimens.-USNM 126403-126432, 

126467, 126468, 126470, 126474-126507. 

Family ANOPLOTHECIDAE 

Subfamily COELOSPIRINAE 

Genus COELOSPIRA Hall, 1863 

Coelospira sp. 

Plate 15, figures 25-32 

Discussion.-Several localities in Somerset County yielded shells with external ornamentation and 

internal features of Coelospira, but the material is 

inadequate for specific determination. Figured Hardwood Mountain specimens are of Silurian rather 

than Devonian aspect. 

Occurrence.-USGS locs. 3499-SD, 3469-SD, 

3488-SD, 3483-SD, 3496-SD, 2806-SD, Spencer 
SYSTEMATIC PALEONTOLOGY 39 

Lake quadrangle, loc. 5995-SD, Attean quadrangle, 

Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian), Beck Pond Limestone 

(Lower Devonian), and McKenney Ponds Member 

of Tarratine Formation (Lower Devonian). 

;Figured specimens.-USNM 126007,A,AA,C, 

160131, 160132A,B, 160133. 

Unfigured specimens.-USNM 126402. 

Suborder SPIRIFEROIDEA 

Superfamily DEL THYRIDACEA 

Family EOSPIRIFERIDAE 

Subfamily EOSPIRIFERINAE 

Genus HEDEINA Boucot, 1957 

Hedeina cf. H. macropleura (Conrad, 1840) 

Plate 15, figures 33-35 

Discussion.-Single brachial valve from Beck 

Pond Limestone and two fragmentary pedicle valves 

from McK·enney Ponds Member of Tarratine Formation possess characteristic fine ornamentation of 

eospiriferids and coarse ornamentation characteristic of H edeina. Specimen from Beck Pond Limestone 

has cardinalia identical with those of eospiriferids 

but is too poorly preserved to be specifically assigned 

without doubt. Material from McKenney Ponds 

Member certainly belongs to H edeina as evidenced 

by broad, flat sulcus and rounded lateral costae, but 

its specific identity is in doubt. Material from 

McKenney Ponds Member might have been reworked 

from preexisting strata of Beck Pond Limestone 

which were removed by erosion before deposition of 

the Tarratine Formation. 

Occurrence.-USGS locs. 3499-SD, 2810-SD, 

2806-SD, Spencer Lake and Pierce Pond quadrangles, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian) and McKenney Ponds Member of 

the Tarratine Formation (Lower Devonian). 

Figured specimens.-USNM 126006, 126076. 

Family DEL THYRIDIDAE 

Subfamily DEL THYRIDINAE 

Genus DEL THYRIS Dalman, 1828 

Delthyris cf. D. kozlowskii Amsden, 1951 

Plate 16, figures 1-5 

Exterior.-Unequally biconvex shells, brachial 

valve gently convex, pedicle valve subconical. Shell 

transversely elongate, outline elliptical. Greatest 

width located at straight hinge line. Brachial valve 

bears low rounded fold ; pedicle valve has corresponding sulcus. Anterior commissure uniplicate, gently 

crenulate. Lateral margins evenly rounded. Pedicle 

valve interarea steeply apsacline, slightly concave 

posteriorly, brachial valve interarea orthocline. Pedicle valve interarea about two-thirds as long as pedicle valve, brachial valve interarea very short. Delthyrium narrow, including an angle of about 20°. 

Deltidial plates narrow, located normal to interarea. 

Not determined if they are apically conjunct. Two or 

three low rounded plications separated by broad interspaces each flank. Radial striations terminate in 

fringe of spines on edge of each growth lamella. 

Pedicle valve interior.-Median septum extends 

about three-quarters distance to anterior margin, 

bisects delthyrial cavity, and is laterally flanked by 

dental lamellae. Median septum very high posteriorly, slopes steeply in anterior direction. Dental 

lamellae subparallel, extend anteriorly about onethird length of valve. Nature of hinge teeth undetermined. Impressions of muscle field not discernible. 

Interior gently crenulated by impress of external 

coarse ornamentation. 

Brachial valve interior.-Medially conjunct hinge 

plates, postero-median portions excavated and crenulated lby slits of ctenophoridium. Hinge 1;>lates supported laterally by fulcral plates that floor dental 

sockets. Myophragm bisects area of muscle attachment to about midlength. Muscle field itself not 

discernible. 

Comparison.-Maine material is similar to Delthyris kozlowskii, but lack of adequate material prohibits positive identification. 

Foerste (1903, p. 710; 1909, p. 92, pl. 2, figs. 31AB) described a species uReticularia pegramensis," 

that possesses a median septum in the pedicle valve 

as well as dental plates and has all the characteris,tics 

of Delthyris s. s. Foerste's specimens do not, however, possess lateral plications as do most forms assigned to Delthyris. Amsden's species D. kozlowskii 

resembles D. pegramensis in all regards except that 

the former is strongly plicaJted. Some specimens of 

D. kozlowskii from Oklahoma bear very weak lateral 

plications, but none were observed without a trace. 

Maine material shows a transition betw~n strongly 

plicated forms and ones with unplicated flanks. 

Occurrence.-USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Base of Hobbs,town Formation (Upper Silurian). 

Figured specimens.-USNM 126038, 126036, 

126027' 126025. 

Genus HOWELLELLA Kozlowski, 1946 

Howellella 1 sp. 

Plate 16, figures 6-7 

Pedicle valve interior.-Short gently diverging 

dental lamellae extend anteriorly about one-fifth 

length of valve. Low myophragm extends slightly 

anterior of dental lamellae. Shell subcircular in outline, highly convex. Hinge line straight, both lateral 
40 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

and anterior margins rounded. Median sulcus; flanks 

bear four to five low rounded costae separated by 

broad interspaces. Muscle field not discernible. 

Discussion.-Only a few poorly preserved impressions of interior of pedicle valve were available. 

Material is not adequate for specific identification. 

Ignorance of fine ornamentation and of brachial 

valve makes generic assignment questionable. 

Occurrence.-VSGS loc. 2950-SD, Spencer Lake 

quadrangle, and 4841-SD, Attean quadrangle, Somerset County, Maine. 

Stratigra.phic location.-Basal part of the Hardwood Mountain Formation (Upper Silurian). 

Figured specimens.-VSNM 126020, 160134. 

Unfigured specimens.-VSNM 126021. 

Howellella? d. H. cyclopterus (Hall, 1857) 

Plate 16, figures 8, 9 

Exterior.-Evenly convex pedicle valve with 

transversely elongate, elliptical outline. Greatest 

width at straight hinge line. Pedicle valve interarea 

apsacline, slightly incurved. Anterior and lateral 

margins rounded. Median sulcus ; flanks bear about 

six costae each. Costae rounded in cross section, 

separated by relatively broad interspaces. Fine ornamentation consists of striations terminating as tiny 

spines on edge each growth lamella. 

Comparison.-N o information is available regarding the interior of the pedicle or brachial valves ; 

therefore, generic assignment is not certain. If shell 

is a delthyrinid, it is similar to H. cycloptera. 

Occurrence.-VSGS loc. 3499-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian). 

'Figured specimens.-USNM 126257 A. 

"Howellella" tomheganensis Boucot, n. sp. 

Plate, 16, figures 10-18 

Exterior.-Shells unequally biconvex, pedicle 

valve slightly more convex than brachial valve. Maximum width slightly anterior of straight hinge line. 

Shells transversely elliptical in outline. Lateral margins sharply rounded, anterior margin gently 

rounded. Brachial valve bears relatively narrow fold 

with subrectangular cross section, may bear indistinct medial groove. Sulcus form corresponds to 

fold, relatively rectangular in cross section. Anterior 

commissure uniplicate, crenulate. Relatively broad, 

rounded plications separated by narrow, relatively 

deep interspaces. Flanks bear seven to ten costae ; 

average about nine. Costae widen anteriorly, show 

no evidence of bifurcation or origin by implantation. 

Pedicle valve interarea apsacline to orthocline, concave posteriorly, and slightly incurved. Brachial 

valve interarea anacline to orthocline. Pedicle valve 

interarea long, that of brachial valve very short. 

Delthyrium includes angle of about 45°, is bordered 

by thin, discrete deltidial plates normal to hinge 

line. Striae terminate in fringes of spines which 

overlap each concentric growth lamella. Sulcus from 

two to three times as wide as first plication lateral 

to it. 

Pedicle valve interi014.-Denta.l lamellae relatively 

short, extend anteriorly from one-fifth to one-third 

of length. Hinge teeth small, located on medial edge 

of hinge line. Muscle field deeply impressed in some 

specimens due to deposition of secondary material, 

weakly impressed in others; flabellate to elongate 

in form, bisected by low myophragm, consists of 

large, anteriorly located diductor impressions and 

pair of small, posteriorly located adductor impressions having rhomboidal outline. Dental lamellae 

diverge between second and third interspace lateral 

of sulcus. Umbonal regions of valve pitted. Peripheral regions of valve crenulated by external ornamentation ; usually one or two fewer plications impressed than present on exterior. Dental lamellae 

indented by steps near edge of delthyrium; these 

steps serving as seats for deltidial plates. 

Brachial valve interior.-Posteriorly located ctenophoridium lateral to which are discrete, basomedially inclined socket plates whose basal margins 

extend below bases of sockets. Posterior face each 

socket plate forms anterior side of socket. Low myophragm bisects area of unimpressed muscle attachment. Interior crenulated by external ornamentation 

impress. 

M easurements.-A plot of p·edicle valve length 

versus width (fig. 15A) shows a see·mingly random 

di'stribution. This is prolbaibly due largely to mechanical deformation plus the fact that only a small 

size range of specimens was available. Relation between pedicle valve width and diductor muscle field 

width is essentially linear and shows a low degree of 

dispersion which may be due to deformation. Width 

of pedicle valve sulcus increases at a constant rate 

relative to valve width (fig. 15C) although a high 

degree of dispersion is present which may be due to 

mechanical deformation. The number of plications 

remains about constant relative to pedicle valve 

width although there is a slight tendency for increase in number with increase in size. Relation 

between pedicle valve width and sulcus width/first 

lateral interspace width is random (fig. 15E), probably due to deformation. Relation between pedicle 

valve width and first lateral interspace width is 

linear (fig. 15F) with high degree of dispersion possibly due to mechanical deformation. Relation of 
SYSTEMATIC PALEONTOLOGY 41 

sulcus and first lateral interspace widths is linear 

(fig. 15G), with a high degree of dispersion. The 

high degree of dispersion shown by the measurements illustrates how mechanical deformation can 

alter characteristics of a sample to rn::tke growth 

rates and a growth curve slope difficult to understand. 

The relation of diductor width and length in the 

pedicle valve is essentially linear, with a low degree 

of dispersion. Relation between pedicle valve width 

and diductor width is essentially linear with a low 

degree of dispersion (fig. 15B). 

Plot of half number of plications against width of 

pedicle valve is normal with mode at nine plications 

(fig. 15D). Slight tendency for increase in number 

of plications from four to five in smaller specimens 

to five and six in larger specimens. 

Comparison.-H.? nerei (Barrande) has a more 

angular and proportionately wider fold than "H." 

tomheganensis. "H." gaspensis, "H" angustiplicata 

var. zaleszczykiensis, and "H." mckenzica have more 

lateral plications than does "H." tomheganensis, 

whereas "H." angustiplicata has fewer plications. 

Occurrence.-USGS locs. 2820-SD, 2750-SD, and 

questionably 2814-SD, Brassua Lake quadrangle, 

Somerset County, Maine. 

Stratigraphic location.-Tomhegan Formation 

(Lower Devonian). 

H olotype.-USNM 126016. 

Figured specimens.-USNM 126032, 125026, 

126017' 126045. 

Measured specimens.-USNM 125889. 

Genus ACROSPIRIFER Helmbrecht and Wedekind, 1923 

Acrospirifer murchisoni (Castelnau, 1843) 

Plate 16, figures 19-25 

Spirifer murchisoni ( Castelnau, 1843), see Clarke, 1900, p. 

46--48, pl. 6, figs. 26-30. 

Exterior.-Unequally biconvex shells, pedicle 

valve about 1112 times as convex as brachial valve. 

Shells transversely elliptical, greatest width at hinge 

line. Short ears present on well-preserved specimens, 

but usually broken off. Brachial valve bears median 

fold with angular cross section, apex rounded. Pedicle valve sulcus corresponds to brachial valve fold. 

Five to seven plications on each flank. Lateral plications have rounded cross section, separated by wide, 

rounded interspaces. Pedicle valve interarea gently 

apsacline, concave posteriorly, beak slightly incurved. Brachial valve interarea gently apsacline to 

orthocline. Pedicle valve interarea relatively long, 

that of brachial valve relatively short. Delthyrium 

open, includes angle of about 90°, bordered by pair 

narrow deltidial plates inserted normal to interarea. 

Anterior commissure uniplicate, crenulate. Lateral 

margins rounded, anterior margin nearly straight. 

Well-preserved specimens have fine, radiating striae 

which terminate as fringe of minute spines over 

anterior edge of each growth lamella. On most specimens fine ornamentation is abraded, shells appear to 

lack spines or striations between plications. Interarea smooth except for growth lines which parallel 

hinge line. 

Pedicle valve interior.-Short dental plates border 

sides of delthyrial cavity but become obsolete in 

larger specimens due to extensive deposition of secondary material in umbonal and delthyrial cavities. 

Hinge teeth stout, triangular in cross section, located medial to hinge line. Muscle field very deeply 

impressed in deposits of secondary material at posterior of valve. Muscle field extends to about midlength, relatively narrow. Consists of pair of median, 

narrow adductor impressions bounded by larger, 

elliptical diductor impressions. Posterior face of delthyrial cavity bounded by rhomboidal impression of 

pedicle callist produced anteriorly, by deposition of 

secondary material, to a point forward of posterior 

tip of diductor impressions. Secondary material laid 

down in umbonal cavities is pitted. Valve peripheral 

regions strongly crenulated by impress of external 

ornamentation. Short myophragm bisects posterior 

part of muscle field. Medial face of each dental plate 

bears step in which to seat a deltidial plate. 

Brachial valve interior.-Ctenophoridium situated 

on posterior wall of notothyrial cavity and laterally 

bounded by narrow, vertically inclined socket plates 

which curve to floor dental sockets. Myophragm bisects unimpressed muscle attachment area. Sockets 

shallow, anterolaterally directed. Interior strongly 

crenulated by external ornamentation impress. 

M easurements.-Relation between length and 

width of pedicle valve is essentially linear with a 

slope of about 60° (fig. 16A). Degree of dispersion is 

not high, actual amount of dispersion incre·ases with 

size, suggesting percentage variation remains about 

constant. Sample is normally distributed. 

Relation of pedicle valve width and first lateral 

interspace width is linear, shows a positive slope of 

about 85° with low degree of dispersion (fig. 16B). 

Relation of pedicle valve width to sulcu:., width is 

linear; slope about 75° indicates sulcus expands at a 

much greater rate than does the first lateral interspace. The degree of dispersion of the sulcus and 

valve width is not .great (fig. 16C). Relation between 

sulcus width and first lateral interspace width is 

curved; strong tendency for the sulcus to increase in 

width at a greater rate than the lateral interspace 

with increase in sulcus width (fig. 16D). Relation 

between pedicle valve width and the ratio of sulcus 
,42 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

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PEDICLE VALVE WIDTH, IN MILLIMETERS 

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DIDUCTOR WIDTH, 

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FIGURE 15.-Measurements of "Howellella" tomheganensis Boucot n. sp. Tomhegan Formation, USGS loc. 282G--SD, Brassua 

Lake quadrangle, Somerset County, Maine. 

width to first lateral interspace width is essentially 

linear but with a much higher degree of dispersion 

than the component measurements suggest, probably 

because the use of ratios tends to multiply the 

amount of variation (fig. 16E). 

USGS Joe. 2720-SD, for the sulcus to expand at 

greater rate than lateral interspace when sulcus 

width of about 3 mm reached. Relationship between 

width of valves and sulcus width/first lateral interspace width and fold width/first lateral plication 

width is · nearly random, because ratios are used. 

Relationship between valve width and widths of 

first lateral plication and interspace is essentially 

linear; moderate degree dispersion which increases 

Relationship between width of fold and sulcus 

with the respective first lateral interspace and plication is linear, with moderate degree of dispersion. 

Slight tendency, in pedicle valves in sample from 
SYSTEMATIC PALEONTOLOGY 43 

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IN MILLIMETERS 

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SULCUS WIDTH, IN MILLIMETERS 

FIGURE 15.-Continued. 

with increase in size at greater rate than if percentage variation remained constant. 

Relationship between pedicle valve width and 

width of the diductor field essentially linear, steeply 

sloping, and indicates the muscle field width increases more slowly than valve width. (fig. 16G) 

Dispersion is low. Relationship between diductor 

width and length is essentially linear with a moderate degree of dispersion (fig. 16F). 

Comparison.-Acrospirifer hartleyi (Schuchert, 

1913) and A. angularis (Schuchert, 1913) are probably synonyms of A. murchisoni, but adequate material is not available for comparison. 

Occurrence.-USGS loc. 3482-SD, 3090-SD, 2847-

SD, 2827-SD, 2890-SD, 2718-SD, 2727-SD, 2729-

SD, 2777-SD, 2705-SD, 2862-SD, 2766-SD, 2834-

SD, 3088-SD, 2089-SD, 2767-SD, Somerset and 

Piscataquis Counties, Maine. 

The following USGS localities provided A. cf. A. 

murchisoni: 2774-SD, 2733-SD, 2792-SD, 2857_..-_Sl), 
44 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

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PEDICLE VALVE WIDTH, IN MILLIMETERS 

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FIRST LATERAL INTERSPACE 

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FIGURE 16.-Measurements of Acrospi'ri/er murchisoni (Castelnau, 1843). Lower sandstone of Tarratine Formation, 

USGS loc. 2718-SD, Long Pond quadrangle, Somerset County, Maine. 
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SYSTEMATIC PALEONTOLOGY 

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OL-__________ L_ ________ ~ __________ _J __________ ~----------~ 

0 10 20 30 40 50 

PEDICLE VALVE WIDTH, IN MILLIMETERS 

FIGURE 16.-Continued. (Continued on following page). 

45 
46 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

6.---------~--------~----~--~~----~~~~------~ 

en 

z 

H 

Q 5r---------~----~~~--~~~--~~~--~-+--------~ 1-

<{ 

(.) 

....1 

c.. 

LL 

0 

a: 

w 

~ 4r---------~----~---+----~~--~--------~--------~ :::> 

z 

w 

J: 

ILL 

....1 

<{ 

J: w 3r---------~---------4----------+----------+--------~ 

z 

0 

2~--------~--------~----------~--------~--------~ 

0 10 20 30 40 50 

PEDICLE VALVE WIDTH, IN MILLIMETERS 

FIGURE 16.-Continued. 

2725-SD, 2810-SD, 2864-SD, 3474-SD, 2806-SD, 

2824-SD, 2797-SD, 2832-SD, 2717-SD, 2691-SD, 

2710-SD, 2861-SD, 2735-SD, 2769-SD, 2837-SD, 

Somerset County, Maine. 

Stratigraphic location.-Seboomook Formation 

(Lower Devonian), McKenney Ponds Member of the 

Tarratine Formation (Lower Devonian), and the 

upper and lower sandstones of the Tarratine Formation (Lower Devonian). 

Figured specimens.-VSNM 126047, 126042, 

126043, 127386. 

Measured speci1nens.-VSNM 125863-125864. 

Unfigured specimens.-VSNM 126526-126556, 

126565-126568. 

Acrospirifer atlanticus (Clarke, 1907) 

Plate 17, figures 1-9 

Spirifer primaevus Steininger var. atlanticus Clarke, 1907, 

p. 260-262. 

Spiri/er gaspensis Williams and Breger, 1916, p. 107-113, pl. 

4, fig. 7, non Billings, 1874. 

Exterior.-Vnequally biconvex shells, pedicle 

valve having greater degree convexity. Greatest 

width at straight hinge line. Shell outline subcircular to alate, deformation altered outlines to a certain extent. Brachial valve bears broad, median fold 

with angular cross section, pedicle valve has corresponding sulcus. Pedicle valve interarea apsacline, 

concave posteriorly, beak slightly incurved. Brachial 

valve interarea gently anacline. Pedicle valve interarea long, brachial valve interarea short. Pedicle 

valve delthyrium includes angle of about 60°-90°, 

laterally bordered by pair narrow deltidial plates 

inserted normal to interarea. Six to 14 lateral plications, depending on width of valve, 10 to 12 usual 

number among specimens studied. Anterior commissure uniplicate, crenulate. 

Radial striae terminate as fringe of spines over 

anterior margins of each growth lamella. Fine ornamentation variably preserved depending upon degree abrasion undergone by specimen; some shells 

partly smooth, partly striate, and partly fimbriate. 

Lateral margins gently rounded, anterior margin 

almost straight. Interarea smooth except for growth 

lines which parallel hinge line. 

Pedicle valve interior.-Short, bladelike hinge 

teeth on medial side hinge line, supported by short, 

dental lamellae which are convex medially. Dental 

lamellae largely obsolete due to deposition of secondary material in umbonal cavities. Muscle field 

deeply impressed, restricted to posterior half of 

valve. Muscle field relatively elliptical to subcircular 

in outline, consists of narrow, median adductor impressions flanked laterally by elongate, anteriorly 

expanding diductor impressions. Diductor impressions striate, extend posteriorly into pair of pointed 

chambers excavated in secondary material deposited 

in delthyrial cavity. Pad of secondary material 

slightly anterior of posterior part of diductor im-
SYSTEMATIC PALEONTOLOGY 47 

pressions bears relatively small, diamond-shaped 

pedicle callist. Interior deeply impressed by external 

ornamentation. One to five fewer lateral plications 

impressed on interior than are present on valve 

exterior. 

Brachial valve interior.-Gtenophoridium located 

on posterior face of notothyrial cavity, laterally 

flanked by pair of socket plates whose lower medial 

edges do not extend below base of sockets. Myophragm bisects unimpressed muscle field and reaches 

to about the midlength. 

Measurements.-The relationship between length 

and width of pedicle valve is linear (fig. 17G). The 

high degree of dispersion suggests mechanical deformation altered the expected distribution. 

The width of sulcus increases linearlv with increase in width of pedicle valve (fig. 17 A), with a 

moderate degree of dispersion. The width of the first 

lateral interspace increases linearly with relation to 

the pedicle valve width (fig. 17B), but the slope is 

much lower than that for the sulcus width, indicating that the sulcus expands at a greater rate than the 

first lateral interspace. The relationship between 

sulcus width and first lateral interspace width is 

linear, with a moderate degree of dispersion (fig. 

17C). The low slope indicates sulcus expands at 

greater rate than interspace. The relationship between pedicle valve width and the ratio of sulcus 

width to first lateral interspace width is linear, with 

a very high degree of dispersion (fig. 17E), induced 

by the use of the ratio; however, it indicates that the 

sulcus becomes proportionately wider witn increase 

in width of pedicle valve, that is, it flares anteriorly. 

The relationship between pedicle valvP width and 

number of lateral plications on one side of sulcus is 

linear, with a low slope, and a moderate degree of 

dispersion (fig. 17F). Smaller specimens average 

about six plications on each side of the sulcus, larger 

ones about ten. Relation between widt}l and length 

of diductor field is linear, with an increasing degree 

of dispersion with increase in size (fig. 17D). Slope 

of about 45 o suggests muscle field expands about 

equally in both directions. 

Comparison.-Acrospirifer intermedius (Hall, 

1859) has fewer lateral plications than A. atlanticus. 

Discussion.-Clarke (1909, p. 83, pl. 19, figs. 5-

12) erroneously cited Tomhegan Point as the locality 

for specimens having the same aspect as those from 

adjacent Baker Brook Point. Rocks of Tomhegan 

Point belong to the Tarratine Formation; those of 

Baker Brook Point belong to the Tomhegan 

Formation. 

The material cited as "Spirifer cf. S. rluodena1·ius 

(Hall)" by Williams and Breger (1916, p. 104-105, 

pl. 4, figs. 3-4) is small specimens of A. atlanticus. 

Williams and Breger's locality 1061 B', cited as 

Little Brassua Lake (1916, p. 109), was not reexamined; may actually refer to mouth of Stony Brook, 

as judged from lithology of their specimens. 

Small specimens of A. atlanticus, less than about 

3 em in width, are difficult to distinguish from A. 

murchisoni, owing to similar shape and ornamentation. 

Occurrence.-USGS locs. 2852-SD, 2820-SD, 

2873-SD, 2750-SD, 2752-SD, 2841""""SD, ~842-SD, 

Brassua Lake quadrangle, Somerset County, Maine. 

The following localities provided A. cf. A. atlanticus: 

2840-SD, 2730-SD, 2723-SD, 2814-SD, 2839-SD, 

Brassua Lake quadrangle, Somerset County, Maine. 

Stratigraphic location.-Tomhegan Formation. 

Figured specimens.-USNM 126041, 126019, 

126031, 126163, 127388. 

Measured specimens.-USNM 125866, 125865. 

Unfigured specimens.-USNM 125939, 126557-

126564, 126578. 

Acrospirifer sp. 1 

Plate 17, figures 10-14 

Exterior.-Shells subequally convex. Greatest 

width at straight hinge line. Shells transverse. 

Brachial valve bears fold with low rounded to almost 

flat cross section, pedicle valve has corresponding 

sulcus. Seven to eight plications each flank. Costae 

have rounded cross section, separated by rounded 

interspaces. Lateral margins rounded, anterior margins almost straight. Concentric growth lines crossed 

by radial striae terminating as fringe of spines 

over anterior margin each lamella. Anterior commissure uniplicate, crenulate. Pedicle valve interarea 

apsacline, beak slightly incurved. Delthyrium open, 

includes angle of about 60°. Delthyrium probably 

bordered by pair narrow deltidial plates. Pedicle 

valve interarea relatively long, brachial valve interarea relatively short. 

Pedicle valve interior.-Short dental lamellae almost entirely obsolete due to deposition secondary 

material in umbonal cavities. Medial face each dental 

lamella indented by step which probably served to 

seat deltidial plate. Muscle field deeply impressed in 

secondary material which lines delthyrial cavity and 

posterior part of valve. Muscle field tripartite, consists of elongate, median adductor impression laterally bounded by pair anteriorly expanding diductor 

impressions. Peripheral regions crenulated by impress external ornamentation. 

Brachial valve interior.--Small ctenophoridium 

located posterior face notothyrial cavity, laterally 

flanked by discrete socket plates directly attached 

to shell walls. Muscle field not impressed, myo-
48 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

20.-------~--------~------~--------~------~--------~----~~--------~-------. 

•CI'J :Co: 

1-l.U 

01-

A 0 0 

~~ ~~ 10r-------~--------~-------+------~+-~--~ •• ~----~--+--------+--------~~----~ 

(.)~ 

3:E 

CI'J2 ··-: 

10 20 30 40 50 60 

PEDICLE VALVE WIDTH. IN MILLIMETERS 

70 80 90 

w 

(.)CI'J 20.-------~--------~------~--------~------~--------~------~--------~-------. 

~a: B VJW a:lww 

1-:E 

z- _...J 

...J~ <C:E 10r-------~--------~-------+--------+--------+--------+--------+--------~------~ 

ffi~ 1- • <C:::c 

...Ji1-0 

~~ ....... .. . . .. · .. 

u:: 00 10 20 30 40 50 60 

PEDJCLE VALVE WIDTH, IN MILLIMETERS 

70 80 90 

20.-------~--------~------~--~----~------~ :::c 

1-

(!) 

20~------~--------~------~ 

c 

1 2 3 4 5 

D 

2VJ 

wa: 

...Jw 

oi-

...Jw 

w :E 1 0 f------__._-+-=---------+--------~ u::~ ... : ...J a:-

o:E 

t>~ ::::> 

0 

0 

.. 

.. 

··.· 

10 20 30 

FIRST LATERAL INTERSPACE WIDTH, IN MILLIMETERS DIDUCTOR FIELD WIDTH, 

IN MILLIMETERS I 

FIGURE 17.-Measurements of Acrospirifer atlanticus (Clarke, 1907). Tomhegan Formation, USGS locs. 2750-SD, 2820-

SD, and 2873-SD, Brassua Lake quadrangle, Somerset County, Maine. 

phragm extends to about midlength. Interior crenulated by impress of external ornamentation. 

Comparison.-Material morphologically unlike 

other acrospiriferids known to me. 

Occurrence.-VSGS loc. 2796-SD, Pierce Pond 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Lower sandstone of the 

Tarratine Formation (Lower Devonian). 

Figured specimens.-VSNM 126090, 126075. 

Acrospirifer sp. Z 

Plate 18, figures 1-5 

Exterior.-Subequally biconvex shells, both valves 

very gently convex. Greatest width at straight hinge 

line. Lateral and anterior margins rounded. Brachial 

valve bears broad, low median fold with very low, 

rounded cross section. Pedicle valve has a sulcus 

corresponding to brachial valve fold. Low, rounded 

costae, about five or six on each flank, separated by 

low, rounded inters paces. Anterior commissure uniplicate, crenulate. Pedicle valve interarea gently 

apsacline, slightly concave. Brachial valve interarea 

orthocline to gently anacline. Pedicle valve interarea 

relatively long, brachial valve interarea relatively 

short. Interarea smooth except for growth lines 

which parallel hinge line. Concentric growth lines 

crossed by striae terminate as fringe of spines over 

anterior edge growth lamellae. Delthyrium includes 
w 

u 

<( 

0.. 

SYSTEMATIC PALEONTOLOGY 49 

5,---------.---------,---------,---------,---------.---------.---------.---------.--------, 

E 

~ 4~--------r---------r---------r---------+---------+---------~--------r---------r-------~ 

w 

1-

z 

...J 

<( 

a: 

~ 3r---------r---------r---------r-~------+-------~~--------+---------+---------+-------~ <( 

...J 

li; 

a: 

LL 

en a 2~--------·r---------r---------r---------+---------+---------+---------r---------r-------~ 

...J 

:::::> 

en 

10 20 30 40 50 60 

PEDICLE VALVE WIDTH, IN MILLIMETERS 

LL 20,---------.---------r---------,---------.------- Oen 

a:w 

wu 

m<C 

F 

::2;0.. 

:::>en zffi 

70 80 90 

~~lOr---------+---------+---------~--------+---------~--------~--------~--~~--~------~ 1--

LL...J 

...J<( 

<(a: 

~~ W<( 

Z...J 

0 

en 

a: 

w 

1-

w 

I 

I 

10 20 30 40 50 60 

PEDICLE VALVE WIDTH, IN MILLIMETERS 

70 80 90 

40,---------,---------,---------.---------.-~ ~---,---------,---------.-------- ~---------~ 

G 

::2: 30r---------r---------r---------+---------+---------+---------~--------r---------~------~ ...J 

...J 

::2: 

z 

::r:' 

b 20r---------r---------+---------+-~------+---------+---------+---------+---------r-~----~ z 

w 

...J 

w 

> 

...J 

<( 

> 

.. w 1or---------r---------r-~------+---------+---------+---------r---------r---------~------~ 

...J 

u 

Cl 

w 

0.. 

10 20 30 40 50 60 70 80 90 

PEDICLE VALVE WIDTH, IN MILLIMETERS 

FIGURE 17.-Continued. 
50 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

angle of about 60°, partly closed in apical region by 

convex plate. 

Pedicle valve interior.-Hinge teeth stubby, situated inner margins hinge line. Dental lamellae short, 

almost entirely obsolete due to deposition secondary 

material in umbonal cavities. Muscle field deeply 

impressed in secondary material lining rear of valve. 

Muscle field consists of median adductor impression 

with subparallel sides flanked by pair laterally expanding diductor impressions. Short myophragm 

divides posterior half muscle field, ends against 

pedicle callist, on diamond-shaped pad of callous, 

just anterior of tips of diductor impressions. Peripheral regions crenulated by impress of external 

ornamentation. 

Brachial valve interior.-Ctenophoridium situated 

rear of notothyrial cavity, laterally flanked by pair 

discrete socket plates attached directly to valve 

walls. Adductor impressions deeply impressed 

posteriorly, fade anteriorly, bisected by short 

myophragm. 

Comparison.-Form unlike other acrospiriferids 

known to me. 

Occurrence.-VSGS loc. 2872-SD, Pierce Pond 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Lower sandstone of the 

Tarratine Formation (Low·er Devonian). 

Figured specimens.-VSNM 126089, 126113. 

Genus ANTISPIRIFER Williams and Breger, 1916 

Antispirifer harroldi Williams and Breger, 1916 

Plate 18, figures 6-14 

Antispirifer harroldi Williams and Breger, 1916, p. 116-117, 

pl. V, figs. 1-13. 

Exterior.-Shells unequally convex, brachial valve 

more convex than relatively flat pedicle valve. Maximum width shell is at straight hinge line. Brachial 

valve bears median fold, broad, gently rounded or 

subrectangular cross section, pedicle valve bears 

corresponding sulcus. Anterior part sulcus pedicle 

valve very steeply inclined as opposed to very gently 

inclined posterior part. Four to seven angular plications on each flank separated by narrow interspaces. 

Closely spaced growth lamellae crossed by striations 

terminating as fringes of spines over anterior edge 

each growth lamella. Deltidial plates not observed, 

delthyrium includes angle about 60°-90°. Pedicle 

valve interarea very gently apsacline, long, brachial 

valve interarea short, anacline. 

Anterior commissure uniplicate, crenulate. Lateral 

margins evenly rounded, anterior margin gently 

rounded to straight. Anterior part pedicle valve approaches resupinate condition. Measurements indicate sulcus ceased widening when pedicle valve 

attained width of about 23 mm, although shell still 

capable of growing wider. Ratio of sulcus width to 

first groove width usually between 2.0 and 3.0, averages about 2.5. Anterior part of fold in shells more 

than about 15 mm wide tends to expand more rapidly 

than adjacent plications, probably due to lateral 

part of fold extending down over lateral margins 

of sulcus. Fold tends to stop expanding in width 

after shell attains width of about 23 mm, as for 

sulcus. 

Pedicle valve interior.-Pedicle valve dental lamellae short, rapidly obsolescent with increasing valve 

size. Muscle field small, subcircular in outline, restricted to posterior part of valve. Hinge teeth low, 

stout, situated along lateral edges delthyrium. Muscle field tripartite, consists of median, elongate, anteriorly expanding adductor impression laterally 

flanked by pair laterally expanding diductor impressions. Posterior tips diductor field extend into secondary material lining delthyrial cavity as two pits 

separated by ridge bearing pedicle callist. Peripheral 

regions of valve strongly crenulated by impress external ornamentation. Secondary material lines posterior part of valve, renders surface relatively 

smooth. About one less lateral plication tends to 

be impressed on interior than is present on exterior. 

Bra.chial valve interior.-Small ctenophoridium 

located posterior face notothyrial cavity, laterally 

flanked by pair of socket plates whose basal margins 

do not extend below bottom of sockets. A few specimens possess basally supporting crural plates whose 

basal margins extend below bottom of sockets medially, indicating howellellid derivation this group 

of shells. Muscle scars weakly impressed, consist of 

pair adductor impressions noticeable only at posterior of notothyrial cavity, and separated by low 

myophragm. Spire observed in one specimen but 

exact nature not worked out. 

Measurements.-The relationships between length 

and width of the pedicle and brachial valves is essentially linear, with a moderate degree of dispersion 

(figs. 18B-E). The distributions are normal, and the 

mode of brachial valves from USGS loc. 2720-SD is 

much larger than for pedicle valves in the same bed, 

suggesting that sorting was important in the creation of the assemblage. Plots for both valves show 

about the same degree of dispersion from both samples suggesting deformation was not important in 

molding either sample. 

The number of plications relative to valve width is 

normally distributed (figs. 18F -/), five being the 

number usually present on each half of either valve. 

Smaller specimens tend to have three to five plication; larger ones five to seven. 

A linear relation exists between width of valves 
SYSTEMATIC ·PALEONTOLOGY 51 

and the respective fold and sulcus (figs. 18A, K, L). 

Degree of dispersion increases rapidly with size, to 

such an extent that there is a suggestion that a 

greater percentage of variation has been introduced 

in the larger specimens. 

Other measurements are shown on figure 18. 

Discussion.-Schuchert (in Pirsson and Schuchert 1914, p. 223) described species subsequently 

described by Williams and Breger (1916. pp. 114-

118) as A. harroldi, but he cited some specimens 

figured by Clarke (1909, pl. 20, figs. 9-12) as cotypes. Unfortunately, the material figured by Clarke 

is too poorly pres·erved to be generically identifiable, 

therefore not clear if Schuchert's species "Spirifer" 

pirssonae is synonymous with A. harroldi. 

Caster's (1939, p. 156-159) "Acrospirifer olssoni" 

as judged from plates and descriptions probably belongs to Antispirifer. Lack of adequate Colombian 

material prevents specific comparison; Caster's 

plates indicate that South American and North 

American species are very similar. 

Occurrence.-USGS locs. 2722-SD, 2721-SD, 

2720-SD, 2765-SD, 2823-SD, 2719-SD, 2783-SD, 

2821-SD, 2861-SD, Somerset County, Maine. 

Stratigraphic location.-Lower sandstone of the 

Tarratine Formation (Lower Devonian) and the 

Tarratine Formation. 

Figured specimens.-USNM 126040, 126039, 

126034, 126028, 126024, 126033. 

Unfigured specimens.-USNM 126265-126271. 

Measured specimens.-USNM 125818, 125844-

125846. 

Genus COSTELLISPIRIFER Bo~cot, new genus 

Type species.-Spirifer perimele Clarke, 1907, p. 

253-254. 

Diagnosis.-Costellispirifer characterized by numerous closely spaced costellae separated by narrow, 

V -shaped interspaces. Costellae have gently rounded 

cross section. Crural plates abs·ent under socket 

plates. Fold has rounded cross section. 

Costellispirifer perimele (Clarke, 1907) 

Plate 18, figures 15-20 

Exterior.-Unequally biconvex shells, pedicle 

valve having greater degree convexity. Greatest 

width at straight hinge line. Lateral and anterior 

margins rounded. Brachial valve bears broad, median 

fold with low, rounded cross section, pedicle valve 

has corre.sponding sulcus. Shells subcircular to 

transversely elongate. Eight to fifteen costellae on 

each flank. Costellae have low, rounded cross section 

separated by narrow v-shaped interspaces. Medially 

located costellae tend to bifurcate anteriorly. Pedicle 

valve interarea gently concave posteriorly, gently 

apsacline to orthocline, brachial valve interarea 

orthocline to gently anacline. Pedicle valve interarea 

relatively long, brachial valve interarea relatively 

short. Delthyrium open, includes angle of about 60°, 

laterally bordered by narrow, discrete deltidial plates 

inserted normal to interarea. Anterior commissure 

uniplicate, crenulate. Radial striae terminate as 

fringe of minute spines over anterior edge each concentric growth lamella. 

Pedicle valve interior .-Short dental plates support stubby hinge teeth, laterally border weakly to 

moderately well impressed muscle field. Dental 

lamellae become increasingly obsolete in large shells 

due to deposition secondary material in umbonal 

cavities. Muscle field narrow, may extend to midlength or point about three-quarters distance to 

anterior margin. Muscle field consists of median, 

narrow adductor track divided by low myophragm, 1 laterally bounded by pair narrow diductor impressions. Interior of shell strongly crenulated by impress external ornamentation. 

Brachial valve interior.-Sm·all ctenophoridium 

located on posterior wall of notothyrial cavity, laterally bounded by anterolaterally diverging socket 

plates whose lower margins are not supported by 

crural plates. Short myophragm bisects unimpressed 

area of muscle attachment. 

Measurements.-The relationship between length 

and width of the pedicle valve is essentially linear, 

with a high degree of dispersion (fig. 19A). The 

high degree of dispersion is probably due t.o mechanical deformation affecting most fossils at this locality 

(USGS loc. 2750-SD). The pedicle valve has about 

eight ro fourteen cOSJtellae on each half of the valve, 

with the mode at albout eleven (fig. 19B). Relation 

between sulcus width and first lateral interspace 

width is linear in the region studied, with a high 

degree of dispersion, and an acute change in slope, in 

the region, of about 1 mm lateral interspace width is 

indicated (fig. 19C) . Relationship betwe·en pedicle 

valve width and first lateral interspace width is 

linear, with a high degree of dispersion (fig. 19D). 

Relation of sulcus width and pedicle valve width is 

linear (fig. 19E). Relation of pedicle valve width to 

the ratio between width of sulcus and first lateral 

interspace is linear (fig. 19F), suggesting sulcus 

width increases at a greater rate than first lateral 

interspace width. Relationship between width of 

pedicle valve and diductor width is linear (fig. 19G). 

Comparison.-C. perimele may be conspecific with 

material described from Highland Mills, N. Y. (Boucot, 1959b). Specimens assigned by Dunbar ( 1919, 

p. 87) to "Spirifer" worthenanus and 11Spirifer" 

engelmanni may belong to Costellispirifer but inade-
52 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

6 30.----------.-----------.----------. en 

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BRACHIAL VALVE WIDTH, IN MILLIMETERS 

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BRACHIAL VALVE WIDTH, IN MILLIMETERS 

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PEDICLE VALVE WIDTH, IN MILLIMETERS 

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PEDICLE VALVE WIDTH, IN MILLIMETERS 

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BRACHIAL VALVE WIDTH, IN MILLIMETERS 

FIGURE 18.-Measurements of Antispirifer harroldi Williams and Breger, 1916. Lower sandstone of Tarratine Formation, Long Pond quadrangle, Somerset County, Maine. A, brachial valve width versus width of fold; USGS 

loc. 2721-SD. B, length versus width of pedicle valves; USGS loc. 2720-SD. C, length versus width of pedicle 

valves; USGS loc. 2721-SD. D, length versus width of brachial valves; USGS loc. 2720-SD. E, length versus 

width of brachial valves; USGS loc. 2721-SD. 
~ 

a: 

w 

1-

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...J 

...J 

SYSTEMATIC PALEONTOLOGY 

~ 30,----------r----------.----------.----------.-----------.---------~ 

a: 

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~ 20~---------+----------+----------4----------~----------~--------~ z 

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> 

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ONE-HALF THE NUMBER OF LATERAL PLICATIONS 

~ 30 a: 

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ONE-HALF THE NUMBER OF PLICATIONS 

FIGURE 18.-Continued. 

F, width of brachial valve versus one half the number of lateral plications; USGS loc. 2721-SD. G, 

width of brachial valve versus one half the number of plications; USGS loc. 2720-SD. H, width 

of pedicle valve versus one half the number of external plications; USGS loc. 2720-SD. (Continued 

on following page). 

53 
54 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

30r---------~----------~---------.----------.-----------.----------.----------. (/) 

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..J 

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~ 20~--------~--------~----------+----------+----------r----------r--------~ z 

I 

1-

Cl 

~ 

w 

~ 10~---------+----------+---------~----------~----------~---------+--------~ <( 

> 

w 

..J 

(.) 

Cl 

w 

0.. 

C/) 

0:: 

w 

1-

w 

~ 

2 3 4 5 6 7 

NUMBER OF PLICATIONS ON LEFT SIDE 

30r---------~----------~---------.-----------.----------r----------.----------. 

J 

. . ..J 20~---------+----------+---------~---------,T~----~~--r-----~---+--------~ ..J 

~ 

z 

I. 

1-

Cl 

. . .. ~ 10~--------~--------~----------+----------+----------~--------~--------_, 

C/) 

::::> 

(.) 

..J 

::::> 

C/) 

C/) 

0:: 

w 

1-

w 

~ 

..J 

..J 

.. 

OL---------~----------~--------_J----------~----------L----------L--------~ 

0 2 3 4 5 6 7 

PEDICLE VALVE WIDTH, IN MILLIMETERS 

30~--------~----------~--------~----------~----------~---------.--------~ 

K 

. . • • • • • : • I 

. : .. 

• I 

. . ~ 20r---------~--------~--------~+----------+--~~~ •• -+~~------~--------~ 

z 

I 

1-

Cl 

~ 

UJ 

... 

~ 10r----------+----------+---------~----------~----------~---------+--------~ 

<( 

> 

w 

..J 

(.) 

Cl 

w 

0.. QL---------~----------~--------~-----------L--------~L---------~6--------~ 

0 2 3 4 5 7 

SULCUS WIDTH, IN MILLIMETERS 

FIGURE 18.-Continued. 

I, pedicle valV'e width versus number of plications on left side; USGS loc. 2721-SD. J, pedicle valve 

width versus sulcus width; USGS loc. 2721-SD. K, pedicle valve width versus sulcus width; USGS 

loc. 2720-SD. (Continued on following page). 
SYSTEMATIC PALEONTOLOGY 

~ 30r---------~--------~----------~--------~----------.-------~~ 

a: L w 

1-

w 

~ 

...J 

...J . . . ... z ~ 20~--------~--------~~--------4-------~~----------+---~----~ 

::c 

1-

0 

~ 

w 

> 

~ 10~--------~--------~~--------4---------~----------+----------4 

> 

...J 

<( 

::c 

(.) 

<( 

0: 

c:c 

~ 

0: 

w 

1-

w 

OL-________ _L __________ L_ ________ ~--~----_J----------~---------

0 2 3 4 5 6 

FOLD WIDTH, IN MILLIMETERS 

3~--------~----------~--------~--------~----------~---------, 

M 

~ 2~--------~--------~~--------4----------4----------+---------_, 

...J 

...J 

~ 

z 

::c 

1-

0 

~ 

z 

0 

1-

<( 

(.) 

...J 

a.. 

1-

~ 

0: 

u. 

o~------~-b----------~--------4---------~----------+---------~ 

2 3 4 5 6 7 8 

SULCUS WIDTH, IN MILLIMETERS 

FIGURE 18.-Continued. 

L, width of brachial valve versus width of fold; USGS loc. 2720-SD. M, width of sulcus versus width of first 

plication on pedicle valve; USGS loc. 2720-SD. (Continued on ·following page). 

55 
56 

4 

CJ) 

a: 

w 

1-

w 

::?! 3 _J 

_J 

::?! 

z 

J: 

1-

0 2 

~ 

z 

Q 

1-

<( 

(.) 

...J 

a.. 

1-

en 

a: 

LL 

oo 

EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

ffi 3 N 

1--

w 

::?! 

_J 

_J 

::?! 

~ 2~--------,_--------~----------+---~-----+----------+---------~ 

£ 

1-

0 

~ 

w 

(.) 

<( 

a.. 1 CJ) 

0: 

w 

1-

~ 

1-

en 

a: 

u: 0 

1 2 3 4 5 6 7 

SULCUS WIDTH,IN MILLIMETERS 

0 

2 3 4 5 6 

FOLD WIDTH, IN MILLIMETERS 

FIGURE 18.-Continued. 

7 

N, width of sulcus versus first interspace width; USGS loc. 2721-SD. 0, width of fold versus width of first plication on brachial valve; USGS loc. 2720-SD. (Continued on following page). 
30 en 

a: 

w 

1-

w 

~ 

_J 

_J 

~ 20 

z 

:r:" 

1-

0 

~ 

w 

> _J 10 

<( 

> 

w 

_J 

~ 

0 

w 

a.. 

00 

3 

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<( 

a: 

w 

1- en <( a: _J w 

z 1-

0 w 2 

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<( _J 

(.) _J 

_J ~ a.. 

1- ~ en 

ff 6 u. _J 

u. 0 

0 u. 

0 

:X: 1-

1-

0 

~ 

00 

Q 

en 30 a: 

w 

1-

w 

~ 

:::i 

_J 

~ 

z 20 

::x::' 

1-

0 

~ 

w 

> 

..J 10 <( 

> 

_J 

~ 

:X: 

(.) 

<( 

a: 

co 00 

p 

SYSTEMATIC PALEONTOLOGY 

2 

·. ... . . . .\. ,. . . .. . . ··. .. . •;, : • I 

. . 

. 

... . . .. . . . . . .. . 

1 2 3 

3 4 

FOLD WIDTH, IN MILLIMETERS 

R 

4 0 

5 6 7 

... 

1 2 3 

SULCUS/FIRST LATERAL PLICATION SULCUS WIDTH/FIRST INTERSPACE WIDTH 

s 

. . .. . · ... ··: 

·. . .. 

. 

.. 

1 2 

FOLD/FIRST RIB 

. 

. 

. 

3 

en 30~---------r----------~--------~ 

a: 

w 

1-

w 

~ 

_J 

_J 

T 

.. 

z ~ 20~---------+----------+---------~ 

::x::' 

1-

0 

~ 

w 

> _J 

<( 

> 

_J 

<( 

:X: 

(.) 

<( 

a: 

co 

. . . . .. 

.. . .. 

. . . 

10~---------+---------·~·+-~------~ 

oa-- 1 2 3 

FOLD WIDTH/FIRST LATERAL PLICATION 

FIGURE 18.-Continued. 

P, width of fold on brachial valve versus width of first plication lateral to fold; USGS loc. 2721-SD. 

Q, pedicle valve width versus ratio of sulcus/first lateral plication width. R, pedicle valve width versus ratio of sulcus width/first interspace width; USGS loc. 2721-SD. S, brachial valve width versus 

ratio of fold/first rib; USGS loc. 2720-SD. T, width of valve versus ratio of fold width/first lateral 

plication; USGS loc. 2721-SD. (Continued on following page). 

57 

4 
58 

30 

en 

a: u w 

1-

w 

~ 

...J 

...J 

~ 20 

z 

:i 

h 

0 

~ 

w 

~ 10 

<( 

> 

w 

...J 

0 

0 

w 

0.. 

00 

EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

: : . • I : . . . . !· : : . .. . . : : 

2 

en 

a: 

w 

1-

w 

~ 

...J 

...J 

~ 

z 

:i 

1-

0 

~ 

w 

> 

...J 

<( 

> 

w 

...J 

(.) 

0 

w 

0.. 

3 4 

30 

v 

20 

: • I 

10 

: . 

00 2 

• L 

3 

FIRST PLICATION WIDTH, IN MILLIMETERS FIRST INTERSPACE WIDTH, .IN MILLIMETERS 

en 30 a: 

w w 

1-

w 

~ 

...J 

...J 

... . . 

I I 

30 en 

w 

a: X 

1-

w 

~ 

...J 

...J 

~ 20 

z .. ~ 20 z . :i 

1-

0 

~ 

w 

> 

...J 10 

<( 

> 

. . . . :i 

1-

0 

~ . : . w . . > . . . . ...J 10 . <( 

> ...J 

~ 

J: 

(.) 

<( 

a: 

lXI 0 

0 1 2 3 

...J 

~ 

J: 

(.) 

<( 

a: 

lXI 00 4 1 2 

FIRST PLICATION WIDTH, IN MILLIMETERS WIDTH OF FIRST PLICATION LATERAL 

30 en 

a: 

w 

1-

w 

~ 

...J 

...J 

~ 20 

z 

J: 

1-

0 

~ 

w 

y 

~- 1• 

.. 

.. 

.. : . 

~ 10r---------~--------~ 

<( 

> 

w 

...J 

(.) 

0 

w 

0.. 0 '------------'-----------4 

0 10 20 1 

z 

.. 

2 3 4 

DIDUCTOR WIDTH, IN MILLIMETERS 

FIGURE 18.-Continued. 

TO FOLD, IN MILLIMETERS 

5 6 

3 

7 

U, pedicle valve width versus width of first plication; USGS loc. 2720-SD. V, width of pedicle valve versus width of 

first interspace; USGS loc. 2721-SD. W, width of brachial valve versus width of first plication; USGS loc. 2720-SD. 

X, width of brachial valve versus width of first plication lateral to fold; USGS loc. 2721-SD. Y, pedicle valve width 

versus diductor width; USGS loc. 2720-SD. Z, width of pedicle valve versus width of diductor; USGS loc. 2721-SD. 

(Continued on following page). 
FIGURE 18.-Continued. 

SYSTEMATIC PALEONTOLOGY 

en 

a: 

w 

1-

w 

20,---------.----------,-----------

AA, diductor length versus diductor width of 

pedicle valve; USGS loc. 2720-SD. BB, (below) diductor length versus diductor width on 

pedicle valve; USGS loc. 2721-SD. 

~ 

:i 

...J 

~ 

z 

AA 

en 

a: 

w 

1-

w 

~ 

...J 

...J 

~ 

z 

£ 

1-

(!) 

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a: 

0 

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u 

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0 

0 

:::c 

1-

0 

~ 

a: 

0 

t) 

:::> 

0 

0 

10 20 30 

DIDUCTOR LENGTH, IN MILLIMETERS 

8,----------.----------,----------.----------.-----------,----------,----------, 

BB 

7~---------+----------+----------+----------4-----------~---------+---------~ 

6-

5 

4 

3 

2~--------~----------+----------+----------4-----------~---------+--------~ 

2 3 4 5 6 7 8 

DIDUCTOR WIDTH, IN MILLIMETERS 

59 
60 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

40 

A 

en 

a: 

UJ 

fUJ 

~ 30 

...J 

...J 

~ 

~ 

:£ 

f-

(!) 20 z 

UJ 

...J 

UJ 

> 

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<( 

> 

UJ 

...J 10 () 

Cl 

UJ 

0.. 

10 20 30 

PEDICLE VALVE WIDTH, IN MILLIMETERS 

en ffi 20,---------.---------.-------~ UJ 

() fUJ 

~ 

...J 

...J 

~ 

c ~~ enw a:fUJUJ 

~-~ 

~:::; 

en 

a: 

UJ 

fUJ 

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40 

40 

B 

30 

20 

10 . 

o~--------~------~ 

0 10 

ONE-HALF THE NUMBER 

OF INTERIOR COSTELLAE 

20 

2,--------.------.--------.--------· 

D 

~ 10r---------~------~~------~ I 

...J :::! 1 t--------+----------+-------+-------1 <(~ 

fCl 

~ 

en 

::> 

() 

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ffiz f--. 

<(::r: 

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f-Cl 

~~ ::> 0 .___ _______ _,__ ______ ...L__ _____ ____j 

en 0 2 u. 00 3 10 20 30 40 

FIRST LATERAL INTERSPACE WIDTH, 

IN MILLIMETERS 

PEDICLE VALVE WIDTH, IN MILLIMETERS 

FIGURE 19.-Measurements of Costellispirifer perimele (Clarke, 1907). Tomhegan Formation, USGS loe. 2750-SD, 

Brassua Lake quadrangle, Somerset County, Maine. 

quate comparative material is available to make comparison possible. 11Spirifer" cumberlandiae (Hall, 1857) has a longer ventral interarea, tends to be orthocline, brachial 

valve has narrow chilidial plates ; these characters 

are absent in 11S." perimele. 

Occurrence.-USGS locs. 2873-SD, 2750-SD, 

2820-SD, 2730-SD, Brassua Lake quadrangle, Somerset County, Maine. 

Stratigraphic location.-Tomhegan Formation. 

Distribution.-N orthern Maine, possibly northern 

New Hampshire (Boucot and Arndt, 1960) and 

southeastern New York (Boucot, 1959b). 

Figured specimens.-USNM 126035, 126030, 

126037, 126029. 

Measured specimens.-USNM 125888. 

Unfigured specimens.-USNM 126580. 

Subfamily MUCROSPIRIFERINAE 

Genus MUCROSPIRIFER Grabau, 1931 

"Mucrospirifer" d. ''M." macra (Hall, 1857) 

Plate 18, figures 21, 22 

Exterior.-Single pedicle valve internal mold 

available. Transverse, triangular outline, about 

twice as broad as long. Lateral profile deeply convex, with flat catacline interarea, giving shell subpyramidal shape. Few poorly preserved radial plica-
SYSTEMATIC PALEONTOLOGY 61 

40~------~~------~ 40~------~~------~ 40~------~~-------. 

{/) 

0: 

w 

1-

E 

{/) 

0: 

w 

1-

F 

{/) 

0: 

w 

G 

~ 30~------~~------~ ~ 30~-------+--------~ ~ 30~------~r-------~ ~ 

..J 

..J 

..J 

..J ..J 

..J 

~ ~ ~ 

~ ... ~ ~ 

:I: :I: 

5 20r--------+--------~ ~ 20~------~~------~ :I: 

~ 20~--------~------~ 

~ 

w 

> 

..J 

<( 

~ 

w 

> ..J 

<( 

> 

w 

..J 

~ 

w 

> 

..J 

<( 

> 

w 

> 

w 

..J 

u 10~~-----+--------~ u 10~~-----+--------~ d 10~~-----+--------~ 

0 

w 

CL. 

·. 0 w 

CL. 

0 

w 

CL. 

o~------~~------~ 

10 20 0 10 20 20 

SULCUS WIDTH, 

IN MILLIMETERS 

SULCUS WIDTH/FIRST LATERAL 

PLICATION WIDTH 

10 

DIDUCTOR WIDTH, 

IN MILLIMETERS 

FIGURE 19.-Continued. 

tions seen impressed on interior. Sp~ecimen too 

poorly preserved to desc·ribe further external details. 

lnterior.-Pair thin, platelike dental lamellae are 

closely spaced and slightly divergent in apex of 

valve. 

Occurrene.-VSGS loc. 2723-SD, Somerset 

County, Maine. 

Stratigraphic location. - Tomhegan Formation 

(Lower Devonian). 

Figured specimen.-USNM 160135. 

Subfamily COSTISPIRIFERINAE Termier and Termier, 1949 

Genus COSTISPIRIFER Cooper, 194Z 

Costispirifer sp. 

Plate 18, figures 23-26 

Exterior.-Unequally biconvex shells, pedicle 

valve having greater degree convexity than brachial 

valve. Greatest width at straight hinge line. Subcircular outline. Brachial valve bears low, rounded 

fold; pedicle valve has corresponding sulcus. 

Rounded costellae separated by relatively narrow 

interspaces. Anterior and lateral margins rounded. 

Anterior commissure uniplicate, crenulate. Pedicle 

valve interarea gently apsacline, brachial valve interarea steeply anacline. Fold and sulcus costellate. 

Pedicle valve interarea relatively long, brachial 

valve interarea steeply anacline. Fold and sulcus 

costellate. Pedicle valve interarea relatively long, 

brachial valve interarea short. Delthyrium appears 

unmodified, includes angle of about 90°. 

Pedicle valve interior.-Dental lamellae short, almost obsolete due to deposition of secondary material in umbonal cavities. Dental lamellae convex 

medially, support stubby hinge teeth located on 

upper margins delthyrium. Muscle field deeply impressed, subcircular outline. Muscle field restricted 

posterior half valve, consists of paired, elongate, 

median adductor impressions longitudinally striate 

and laterally bounded by paired, anteriorly expanding diductor impressions. Diductor impressions extend posteriorly into pair of pits developed in secondary material lining delthyrial cavity. Anterior 

and medial to posterior end of diductor impres·sions 

is vertical, diamond-shaped, small pedicle callist. 

Peripheral regions crenulated by impress external 

ornamentation. 

BrachiJLl valve interior.-Small ctenophoridium 

laterally bounded by socket plates which diverge 

anterolaterally. Basal part of socket plates not supported by crural plates. Interior crenulated by impress of external ornamentation. 

Comparison.-Maine specimens not specifically 

identifiable. Much of the material has ~been badly 

abraded and the external ornamentation removed. 

Occurrence.-VSGS locs. 3088-SD, 2767-SD, 
62 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

3482-SD, Somerset and Piscataquis Counties, 

Maine. 

Stratigraphic location.-Lower sandstone of the 

Tarratine Formation (Lower Devonian) and Seboomook Formation (Lower Devonian). 

Figured specimens.-USNM 126018, 126023. 

Subfamily KOZLOWSKIELLINAE 

Genus KOZLOWSKIELLINA Boucot, 1958 

Subgenus MEGAKOZLOWSKIELLA Boucot, 1957 

Megakozlowskiella sp. 

Plate 19, figures 1-6 

Discussion.-Poor specimens of M egakozlowskiella were obtained at several localities in Somerset 

County; the material is unfit for specific identification. Specimens from the Beck Pond Limestone have 

steeply apsacline to catacline pedicle valve interarea 

and pseudospondylium formed by deposition of secondary material between converging dental lamellae 

and median septum; in these regards resemble M. 

cyrtinoides. 

Occurrence.-USGS locs. 3477-SD, 3499-SD, 

3601-SD, 3487-SD, 3497-SD, Spencer Lake and 

Pierce Pond quadrangles, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Limestone 

(Lower Devonian) and Parker Bog Formation 

(Lower Devonian) . 

Figured specimens.-USNM 126046, 126044. 

Family AMBOCOELIIDAE 

Subfamily AMBOCOELIINAE 

Genus METAPLASIA Hall and Clarke, 1893 

Metaplasia cf. M. paucicostata (Schuchert, 1913) 

Plate 19, figures 7-11 

Exterior.-Unequally convex shells, gently convex brachial valve, subconical pedicle valve. Outline 

subcircular to transversely elliptical, brachial valve 

more elliptical than pedicle valve. Pedicle valve interarea orthocline or gently apsacline or even gently 

anacline, beak gently incurved. Hinge line straight, 

greatest width near midlength. Delthyrium appears 

unmodified, includes angle of about 60° Cardinal 

margins terebratulid; lateral and anterior margins 

rounded. Shells appear smooth except for concentric 

growth lines. Pedicle valve bears very shallow median furrow flanked by pair ill-defined plications; 

remainder valve smooth. Anterior commissure probably feebly intraplicate. 

Pedicle valve interior.-Inner margins hinge line 

flanked by stubby hinge teeth. Muscle field deeply 

impressed into secondary material lining delthyrial 

cavity. Muscle field longitudinally elongate in form, 

consists paired, median adductor impressions separated by myophragm, laterally flanked by pair narrow diductor impressions. Posterior part delthyrial 

cavity filled by pad secondary material forming medially grooved step, may have served as pedicle 

callist. Umbonal cavities pitted. Pair subparallel 

pallial trunks appear to extend from anterior portion muscle field almost to anterior margin. 

Brachial valve interior.-Small bladelike cardinal 

process laterally flanked by pair elongate crural 

plates forms pseudocruralium in posterior part of 

valve. Well-impressed adductor field anterior of cardinalia is difficult to study on the one specimen available. Valve interior appears smooth. 

Comparison.-Maine specimens appear conspecific 

with Metaplasia pauciocostata from Shriver Chert; 

the lack of adequate comparative material makes 

positive specific assignment ill advised. M. paucicostata may be subjective synonym M. pyxidata; the 

lack of verified specimens of latter leaves this point 

in doubt. 

Occurrence.-USGS loc. 2806-SD, Pierce Pond 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-McKenney Ponds Member of Tarratine Formation (Lower Devonian). 

Figured specimens.-USNM 126115A,B,C. 

Unjigured specimeJU.-USNM 126258. 

Metaplasia minuta Boucot, 1959 

Plate 19, figures 12-18 

Metaplasia minuta Boucot, 1959a, p. 17-18, pl. 2, figs. 18-24. 

Exterior.-Unequally biconvex shells, brachial 

valve gently convex, pedicle valve subconical. Hinge 

lineline straight, maximum width located about onethird distance anterior from posterior margin. 

Valves subcircular to transversely elliptical in outline. Brachial valve bears very low median fold 

flanked by two pairs very low and distinct costae. 

Pedicle valve bears low median furrow flanked by 

one pair prominent costae. Valve surface smooth 

except for concentric growth lines. Pedicle valve 

interarea steeply apsacline to catacline, beak incurved gently. Delthyrium open, includes angle of 

about 30°. Brachial valve interarea very short, appears orthocline, pedicle valve interarea very long. 

Anterior commissure faintly intraplicate. Anterior 

and lateral margins rounded. 

Pedicle valve interior.-Pair stubby hinge teeth 

border sides of delthyrium, tracks leave pair of 

ridges on interior simulating pair short dental lamellae. Low myophragm divides weakly impressed muscle field into pair elongate impressions. Valve interior impressed by plications. 

Brachial valve interior.-Short, bladelike cardinal 

process flanked by crural plates reaching floor of 

valve, form pseudocruralium. Dental sockets floored 

by socket plates which posteriorly unite with crural 

plates. Muscle field weakly impressed, consists of 
SYSTEMATIC PALEONTOLOGY 63 

elongate median adductor impression laterally 

bounded by pair elongate, lateral adductor impressions. 

Comparison.-Maine material appears specifically 

distinct from M. pauciocostata which it closely resembles. Same form occurs in Camden Chert of T·ennessee, but collections of U.S. National Museum do 

not have enough specimens of this species to permit 

a thorough comparison. Plications in this material 

are much stronger than in that from the strata of 

Oriskany age which has been previously assigned to 

M etaplasi;a. 

Occurrence.-USGS loc. 2750-SD, 2852-SD, 2820-

SD, Brassua Lake quadrangle, Somerset County, 

Maine. 

Stratigraphic location.-Tomhegan Formation 

(Lower Devonian) . 

Figured specimens.-USNM 126086, 126110, 

126067. 

Unfigured specimens.-USNM 126597-126600. 

Genua PLICOPLASIA Boucot, 1959 

Plicoplasia plicata (Weller, 1903) 

Plate 19, figures 19-29 

Plicoplasia plicata (Weller, 1903), see Boucot, 1959a, p. 22, 

pl. 1, figs. 1-9. 

Exterior.-Unequally biconvex shells. brachial 

valve gently convex, pedicle valve subconical. Greatest width at straight hinge line, or at position 

slightly anterior. Transversely elliptical outline. 

Brachial valve bears broad, shallow medial medial 

sulcus, pedicle valve bears broad, low median fold. 

Anterior commissure weakly sulcate, crenulate. Posterior part lateral margin straight, remainder and 

anterior margin, rounded. Plications rounded cross 

section, separated by wide, U-shaped interspaces. 

One plication situated in sulcus, each flank bears 

three to four plications including one bounding fold 

or sulcus laterally. Plications bounding fold larger 

than remainder present on shell. Pedicle valve interarea orthocline to gently apsacline, beak straight to 

gently incurved. Pedicle valve interarea relatively 

long, brachial valve interarea short. Brachial valve 

interarea orthocline to gently anacline. Concentric 

growth lines relatively lamellose anteriorly. Delthyrium open, includes angle of about 30°. 

Pedicle valve interior.-Stout hinge teeth situated 

either side hinge line's median edge. Hinge tooth 

track buried in secondary material deposited against 

posterior valve wall. Myophragm bisects muscle 

field, extends anteriorly to about midlength. Muscle 

field weakly discernible. Interior crenulated by plication impress. 

Brachial valve interior.-Prostrate, posteriorly directed, medially grooved, terminally bifid cardinal 

process laterally flanked by basomedially converging crural plates whose lower edges are parallel. 

Dental sockets formed medially by crural plates, anterolaterally by socket plates which bottom them, 

posteriorly by interarea. Dental sockets triangular 

in cross section. Myophragrn. bisects valve, muscle 

field unimpressed. Valve interior crenulated by impress external ornamentation. 

Comparison.-P. plica.ta has a shallower sulcus 

and lower fold than P. cooperi. P. plicata tends to 

have more lateral costae than P. cooperi. 

Occurrence.-USGS locs. 2813-SD. 2811-SD, 

2798-SD, 2797-SD, 3089-SD, and questionably 

3481-SD, 2735-SD, 2731-SD, 3482-SD, 2884-SD, 

Somerset and Piscataquis Counties, Maine. 

Stratigraphic location.-Lower s~andstone of the 

Tarratine Formation (Lower Devonian), and the 

Seboomook Formation (Lower Devonian). 

Distribution.-Eastern North America. 

Figured specimens.-USNM 126114, 126087, 

126106, 126256, 126259, 126260. 

Superfamily CYRTINACEA 

Family CYRTINIDAE 

Subfamily CYRTININAE 

Genua CYRTINA Davidson, 1858 

Cyrtina 7 cf. C. rostrata (Hall, 1857) 

Plate 19, figures 30-32 

Exterior .-Single badly deformed internal mold 

available. Transverse, subtriangular outline, deeply 

unequally biconvex lateral profile. Pedicle valve very 

deep, subpyramidal, with high flat catacline ventral 

interarea. Narrow median pedicle valve sulcus, corresponding low brachial valve fold. Numerous relatively small radial plications; eight or nine discernible on one valve flank. 

Pedicle valve interior.-Specimen too poorly preserved to be certain of internal features; appears 

to be median groove or line of demarcation that may 

have accommodated ventral median septum. 

Brachial valve interior.-Internal structures too 

poorly preserved to afford description. Interior corrugated by impress of radial plications. 

Occurrence.-USGS loc. 2883-SD. Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigrarphic location. - Seboomook Formation 

(Lower Devonian). 

Figured specimen.-USNM 160136. 

Suborder ATHYRIDOIDEA 

Superfamily A THYRIDACEA 

Family MERISTELLIDAE 

Subfamily MERISTINAE 

Genua MERISTA Suess, 1851 

Merista cf. M. tennesseensia Hall and Clarke, 1895 

Plate 20, figu.res 1-6 

Exterior.-Subequally convex shells with longitudinally elongate, elliptical outline. Maximum 
64 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

width near midlength. Cardinal margins pedicle 

valve terebratulid, beak incurved over posterior end 

brachial valve. Lateral and anterior margins 

rounded. Brachial valve bears low broad fold, originating about midlength, pedicle valve bears broad 

shallow sulcus originating in anterior quarter of 

shell. Anterior commissure uniplicate·. Concentric 

growth lines. 

Pedicle v·alve interior.-Well-developed shoe-lifter 

process. Short dental lamellae bound delthyrial 

cavity. 

Brachial valve interior .-Short septali urn supported by median septum which extends anteriorly 

to about midlength. 

Comparison.-Maine material resembles M. te~ 

nesseensis in external form but is inadequate for a 

posi,tive specific identification. 

Occurrence.-USGS loc. 3488-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Hardwood Mountain Formation (Upper Silurian). 

Figured specimens.-USNM 126105, 126085. 

Subfamily MERISTELLINAE 

Genus MERISTELLA Hall, 1860 

Meristella lata (Hall, 1859) 

Plate 20, figures 7-13 

Meristella lata (Hall, 1859), see Clarke, 1900 p. 45. 

Exterior.-Unequally convex sheHs, brachial valve 

having greater degree convexity than pedicle valve. 

Shell outline subcircular to longitudinally elliptical. 

Pedicle valve cardinal margins terebratuloid. Lateral, 

anterior margins rounded. Brachial valve bears low 

fold originating near midlength. The greatest width 

located slightly posterior to midlength. Pedicle valve 

bears broad shallow sulcus. Anterior commissure 

uniplicate. Concentric growth lines. 

Pedicle valve interior.-Short, obsolete dental 

lamellae border delthyrial cavity, support stout hinge 

teeth. Umbonal cavities filled with secondary material. Muscle field deeply impressed into secondary 

material lining posterior part of valve. Muscle field 

flabellate, outline subtriangular, extends anteriorly 

to about three-quarters distance to anterior margin, 

about half as wide as valve. Muscle field longitudinally striate. Posterior part delthyrial cavity filled 

with secondary material into which is indented a 

spherical chamber serving as pedicle callist. 

Brachial valve interior .-Cardinal plate appears 

formed from medially conjunct hinge plates, basally 

supported by medial septum which extends anteriorly three-quarters distance to anterior margin. 

Median part cardinal plate depressed. Spires laterally directed, nature of jugum not ascertained. Spire 

contains about 13 whorls. Dental sockets anteriorly 

directed, partly roofed over by projecting edges of 

. cardinal plate. Muscle field unimpressed. 

Occurrence.-USGS locs. 2810-SD, 2806-SD, 

3089-SD, 2732-SD, 2731-SD, 2722-SD, 2813-SD, 

2776-SD, 3482-SD, 2720-SD, 2777-SD, 2797-SD, 

2719-SD, 2847-SD, 2760-SD, 2798-SD, 2767-SD, 

2701-SD, 2884-SD, 2770-SD, 2729-SD, 2861-SD, 

2721-SD, 2771-SD, Somerset and Piscataquis Counties, Maine. 

Stratigraphic location.-McKenney Ponds Member and upper and lower sandstones of the Tarratine Formation (Lower Devonian), Seboomook Formation (Lower Devonian). 

Figured specimens.-USNM 126103, 126116A, 

126079, 126082, 126261, 127390. 

Unfigured specimens.-USNM 126104, 126469, 

126581-126596. 

Meristella 1 sp. 

Discussion.-Inadequate material of a rostrospiroid that resembles M eristella was obtained at 

several localities in strata of pre-Oriskany age. 

Occurrence.-Localities 3499-SD, 3487-SD, 3477-

SD, Pierce Pond and Spencer Lake quadrangles, 

Somerset County, Maine. 

Stratigraphic location.-Parker Bog Formation 

(Lower Devonian) and Beck Pond Limestone (Lower 

Devonian). 

Unfigured specimens.-USNM 126569-126577. 

Genus CHARIONOIDES Boucot, Johnson and Staton, 1964 

Charionoides doris (Hall, 1866) 

Plate 20, figures 14-22 

Charionoides doris (Hall, 1860), see &mcot, Johnson, and 

Staton, 1964, p. 817-818, pl. 127, figs. 14-20. 

Exterior.-Subequally biconvex shells, pedicle 

valve more convex than gently convex brachial valve. 

Almond-shaped shell outline, maximum width about 

two-thirds distance from posterior. Cardinal margins terebratulid; palintrope elongate, slightly concave. Ventral beak very attenuate. Anterior and 

lateral margins rounded. Concentric growth lines. 

Neither fold nor sulcus present. Delthyrium appears 

closed by pair small plates, except for small mesothyrid foramen. 

Pedicle valve interior.-Short dental lamellae 

laterally bound delthyrial cavity. Muscle field 

weakly impressed in small specimens, in large specimens deeply impressed and flabellate. Muscle field 

subtriangular impression deeply impressed posteriorly, probably represents diductor impressions, posterior of which are small elongate adductor impressions. Pedicle callist located in posterior part 

delthyrial cavity. 

Brachial valve interior.-Sessile cruralium formed 
SYSTEMATIC PALEONTOLOGY 65 

from medially conjunct hinge plates supported by 

low median septum. Brachiophores extend from 

upper parts hinge plates. Median septum bisects 

cruralium base as low ridge. 

Occurrence.-USGS locs. 2750-SD, 2820-SD, 

Brassua Lake quadrangle, Somerset County, Maine. 

Stratigraphic location. - Tomhegan Formation 

(Lower Devonian). 

Figured specimens.- USNM 126111B, 126092, 

126102,126081, 126080A,126117. 

Family NUCLEOSPIRIDAE 

Genua NUCLEOSPIRA Hall, 1859 

Nudeospira sp. 

Plate 20, figures 23-27 

Exterior.-Unequally convex shells, pedicle valve 

having greater degree convexity than brachial valve. 

Shell outline subcircular, greatest width near midlength. Cardinal margins pedicle valve terebratulid. 

Pedicle valve bears shallow, narrow sulcus. Concentric growth lines. Lateral and anterior margins 

rounded. Peripheral region bears series of fine spines. 

Delthyrium unmodified, includes angle of about 90°. 

Pedicle valve interior.-Short tooth tracks border 

delthyrial cavity, support small, stubby hinge teeth. 

Low median septum extends anteriorly to about 

valve midlength. Muscle field unimpressed. Anterior 

of valve smooth. 

Brachial valve interior.-Platelike cardinal process posteriorly reflexed, supported anteriorly by 

short median septum. Narrow adductor impressions 

either side median septum. Anterior of valve is 

smooth. 

Comparison.-Material is inadequate for specific 

identification. 

Occurrence.-USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

Stratigraphic location.-Base of Hobbstown Formation (UPP€r Silurian). 

Figured specimens.-USNM 126091, 126262. 

Family ATHYRIDIDAE 

Subfamily A THYRIDINAE 

Genus PROTATHYRIS Kozlowski, 1929 

Protathyris ap. 

Plate 20, figures 28-37; figure 20 

Exterior.-Shells biconvex, pedicle valve having 

greater degree convexity. Shell outline subcircular 

transversely elliptical. Hinge line curved, much 

shorter than maximum width located near midlength. Pedicle valve beak gently incurved, interarea steeply apsacline to catacline. Pedicle valve 

interarea relatively long, brachial valve interarea 

short. Brachial valve bears broad low fold, pedicle 

valve has corresponding sulcus. Anterior commissure uniplicate. Concentric growth lines. 

Pedicle valve interior.-Short dental lamellae laterally bound delthyrial cavity (fig. 20), posteriorly 

support bladelike, medially directed hinge teeth. 

Muscle field weakly impressed, but appears to consist of elongate muscle field medially divided by low 

broad median septum. Delthyrium not modified. 

Brachial valve interior .-Cardinal plate formed 

from medially conjunct hinge plates, medial trough. 

Brachiophores attached to lateral portions cardinal 

plate. Cardinal plate laterally overlaps anteriorly 

directed dental sockets. Spire present. 

Comparison.-Adequate material is unavailable 

for making specific assignment. The chief differences (with the possible exception of the spiralia 

and jugum, which were not S'tudied) between the 

related genera Greenfieldia and Protathyris are the 

relative degree of valve convexity and the inclination of the ventral intera:rea. Protathyris has a steeply inclined interarea which may be catacline; Gree~ 

fieldia has a gently apsacline to orthocline ventral 

interarea. Protathyris has a more inflated and gibbous aspect than does Greenfieldia. 

Occurrence.-USGS loc. 2822-SD, Attean quadrangle, Somerset County, Maine. 

Stratigraphic location. - Hardwood Mountain 

Formation (Upper Silurian). 

Figured specimens.-USNM 126070, 126262. 

Unfigured specimens.-USNM 126059, 126071. 

Suborder TEREBRATULOIDEA 

Superfamily TEREBRA TULACEA 

Family CENTRONELLIDAE 

Subfamily RENSSELAERIINAE 

Geuua NANOTHYRIS Cloud, 1942 

Nuothyria hodgei Boucot, n. ap. 

Plate 21, figures 1-6 

Exterior.-Shell biconvex, brachial valve gently 

convex, pedicle valve more strongly convex, slightly 

subcarinate form. Shells small. Valves longitudinally 

elongate, subcircular to elliptical outline. Greatest 

width located near midlength. Maximum thickness 

located about one-third to one-half distance anterior 

from beak. Anterior margin rectimarginate, faintly 

crenulate. Cardinal margins subterebratulid. Hinge 

line straight. Pedicle valve beak erect to suberect. 

Planarea one-half to two-thirds as wide as maximum 

width. Umbonal regions smooth, peripheral regions 

faintly costellate. Costellae low, rounded cross section separated by rounded interspaces. Shell thin. 

Pedicle valve interior.-Dental lamellae thin, extend anteriorly about one-fifth maximum length. 

Muscle field feebly impressed. Muscle field appears 

to consist of elongate diductor field medially enclosing small, elliptical adductor impression. 

Brachial valve interior.-Concave cardinal plate 

posteriorly perforate, free, supported basally by dis-
66 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

crete crural plates. Dental sockets narrow, short, 

make angle of about 45° with hinge line. Muscle 

field weakly impressed, medially divided by low myophragm. Narrow, elongate, paired lateral adductors 

slightly impressed posteriorly, enclose medial adductor. 

Measurements. - Relationships among length, 

width, and thickness are linear (fig. 21) with a relatively high degree of dispersion, reflecting the limited size range of the sample. 

Comparison.-N. hodgei is distinct from N. mutabilis. The former has a weaker impress of the 

costellae, less terebratulid outline of cardinal margin, 

and less gibbous lateral aspect. N. hodgei differs 

from N. subglobos.a in its less gibbous lateral aspect 

much less strongly impressed ornamentation, les·s 

terebratulid cardinal margins, and more erect beak. 

N. reesidei has more strongly impressed ornamentation, more terebratulid cardinal margins, and a 

slightly more gibbous profile. N. hodgei differs from 

N. subglobosa crassa and N. subglobosa avus in its 

less well impressed radial ornamentation; its outline less circular than that of N. subglobosa crassa. 

Occurrence.- USGS locs. 2832-SD, 2890-SD, 

2721-SD, 3090-SD, Somerset County, Maine. 

Stratigraphic location.-Tarratine Formation. 

Distribution.-Somerset County, Maine. 

H olo·type.-USNM 126194. 

Measured paratypes.-USNM 125940. 

Figured p,aratypes. - USNM 126191, 126220, 

126183, 125943. 

Unfigured paratypes.-USNM 125941, 125942, 

125944, 125945. 

Nanothyris cf. N. subglobosa (Weller, 1903) 

Plate 21, figures 7-13 

Exterior.-Shell biconvex, gently convex brachial 

valve, more highly convex, carinate pedicle valve. 

Pedicle valve about 1 ~ times as deep as brachial 

valve. Shells elongate, elliptical outline. Maximum 

width situated near midlength or slightly posterior. 

Lateral and anterior margins rounded. Anterior margin rectimarginate, weakly crenulate. Weak costellae 

distributed about periphery, absent in umbonal regions. Cardinal margins subterebratulid. Hinge line 

short, rounded. Pedicle valve beak appears suberect. 

Pedicle valve interior.-Dental lamellae thin, 

short. Muscle field very weakly impressed. 

Brachial valve interior.-Serial sections demonstrate presence of cardinal plate supported by crural 

plates, posteriorly perforate. 

Comparison.-These specimens most closely resemble N. subglobosa but the deformed state of available material precludes positive specific identification. 

Occurrence.-USGS locs. 3601-SD, 3600-SD, 

Spencer Lake quadrangle, Somerset County, Maine. 

Stratigraphic location.-Beck Pond Formation 

(Lower Devonian) . 

Figured specimens.-USNM 126187, 126192 A, B. 

Genua RENSSELAERIA Hall, 1859 

Rensselaeria ap. 

Plate 21, figures 14-17 

Exterior.-Fragmentary exteriors present are 

badly abraded. Pedicle foramen appears submesothyrid. Cardinal margins terebratulid. Pedicle valve 

beak nearly straight. Pedicle valve more strongly 

convex than brachial valve. Lateral margins 

rounded, anterior margins appear rounded. 

Pedicle valve interior.-Dental lamellae short, almost entirely obsolete due to deposition secondary 

material in umbonal cavities. Hinge teeth bladelike, 

inclined basally towards midline. Hinge teeth fused 

basally with dental lamellae. Muscle field deeply impressed, consists of elongate diductor field with 

subparallel sides, posteriorly divided by myophragm 

along which were probably very narrow adductor 

impressions. Secondary material almost fills posterior part of delthyrial cavity, except for deeply 

impressed muscle field. Upper surface of secondary 

material bears pedicle callist. 

Brachial v·alve interior.- Thickened cardinal 

plate, posteriorly perforate, supported by pair crural 

plates. Dental sockets narrow, laterally directed. 

Muscle field weakly impressed, consists of two pairs 

elongate subparallel adductor impressions. Low myophragm medially divides muscle field. 

Comparison.-Maine material too poor to be specifically identified. 

Discussion.-!n regard to the stratigraphic range 

of the genus, Cloud (1942, p. 47) assigned 11Atrypa" 

aequiradiata Conrad, 1842, from the Becraft Limes.tone, to Nanothyris. Reexamination shows it belongs to Renssemeria s. s. because of its radially 

ornamented umbones and internal morphology which 

differ in no important respect from those of the other 

species assigned to Rensselaeria by Cloud (1942), 

p. 55, 56). 

Material assigned by Boucot (in Woodard, 1951, 

p. 76) to uBeachia cf. thunii" belongs to Rensselaeria 

sp. 

FIGURE 20.-Serial sections of specimen of Protathyris sp. (X 4.5). Hardwood Mountain Formation. USGS loc. 2822-SD, 

Attean quadrangle, Somerset County, Maine. Numbers are measureme·nts in millimeters from posterior end of 

shell. 
SYSTEMATIC PALEONTOLOGY 67 

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68 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

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FIGURE 21.-Measurements of pedicle valves of Nanotkyris kodgei Boucot, n. sp. Lower sandstone of Tarratine Formation. USGS loc. 3090-SD, Long Pond quadrangle, Somerset, Maine. 
SYSTEMATIC PALEONTOLOGY 69 

Occurrence.-USGS locs. 2767-SD, 2729-SD, 

Somerset County, Maine. 

Stratigraphic location.-Lower sandstone of the 

Tarratine Formation (Lower Devonian). 

Figured specimens.-USNM 126216, 126214. 

Unfigured specimens.-USNM 126215, 126213. 

Subfamily EURYTHYRIDINAE 

Genus BEACHIA Hall and Clarke, 1893 

Beac:hia thunii {Clarke, 1907) 

Plate 21, figures 18-30; plate 22, figures 1-5 

Megalanteris thunei (Clarke, 1907), p. 168, pl. 26, figs. 8-13; 

pl. 27, figs. 7-15. 

Exterior.-Shell subequally biconvex, subcarinate 

pedicle valve having somewhat greater degree convexity than gently convex brachial valve. Shell subcircular. Pedicle foramen mesothyrid. Small deltidial plates medially conjunct. Anterior commissure 

rectimarginate, feebly crenulate in some specimens. 

Lateral and anterior margins rounded. Cardinal margin subterebratulid. Concentric growth lines, sometimes faintly impressed costellae, particularly peripherally. Pedicle valve beak suberect. Maximum 

width located at midlength. Lateral margins may be 

introverted, but on most specimens this feature not 

evident. 

Pedicle valve interior.-Dentallamellae short, become almost entirely obsolete with increase in specimen size, due to deposition secondary material in 

umbonal cavities. Anterior part dental lamellae bears 

bladelike hinge teeth. Inner face each hinge tooth 

longitudinally grooved to receive lateral margin of 

cardinal plate. Posterior part delthyrial cavity filled 

with secondary material except for site of pedicle 

callist. Diductor field deeply impressed, narrow and 

straight-sided in form, divided medially in posterior 

part of valve by low myophragm. Myophragm bordered by pair narrow adductor impressions. Anterior 

of myophragm is elliptical anterior diductor impression. Interior of valve smooth. 

Brachial valve interior.-Cardinalia of small 

shells consist of discrete hinge plates united anteromedially by narrow band (posterior of band is large, 

triangular foramen). Under hinge plates are supporting crural plates. Muscle field small shells barely impressed, although myophragm prominent. This 

stage brachial valve similar to N anothyris. In large 

specimens cardinalia consist of cardinal plate bearing ponderous, moundlike thickening which serves 

as cardinal process. Foramen in cardinal plate closed 

off as size of cardinal process increases, at same 

time crural plates become almost entirely submerged 

in secondary material. Dental sockets deep, anterolaterally directed. Muscle field consists of posteriorly 

deeply impressed adductor impression divided medially by myophragm. Posteromedial pair adductor 

impressions can be distinguished from pair of elongate lateral impressions in some shells. Pallial marks 

extend toward anterior margin from anterior margins of muscle field, subparallel to midline. Brachiophores bladelike. 

Comparison.-B. thunii does not possess the 

prominent, introverted lateral margins of B. suessana, as judged from material studied, in addition 

the latter species seems to possess more consistently costellate ornamentation. Cardinal process of B. 

thunii is commonly swollen and enlarged whereas in 

B. suessana the cardinal plate is not commonly greatly thickened. 

Specimen questionably referred to M eganteris by 

Cloud ( 1942, p. 109-110) belongs to Beachia thunii. 

Occurrence.-USGS locs. 2813-SD, 2700-SD, 

2701-SD, 2731-SD, 2729-SD, 2732-SD, 2751-SD, 

2792-SD, 2769-SD, 2767-SD, 2776-SD, 2798-SD, 

2803-SD, 2812-SD, 2771-SD, 2777-SD, 2725--SD, 

2830-SD, 2761-SD, 2810-SD, 3482-SD, 3486-SD, 

2806-SD, 2872-SD, 2760-SD, 2870-SD, 3474-SD, 

2864-SD, 2796-SD, 2884-SD, Somerset and Piscataquis Counties, Maine. 

Stratigraphic location.-Seboomook Formation 

(Lower Devonian), and McKenney Ponds Member 

and lower sandstone of the Tarratine Formation 

(Lower Devonian). 

Distribution.-Eastern North America. 

Figured specimens. - USNM 126198-126200, 

126202-126207, 126209, 127217, and New York State 

Museum 8436. 

Unfigured specimens.-USNM 126177, 126605-

126608, 126610-126634. 

Genus CLOUDOTHYRIS Bouc:ot and Johnson, 1968 

Cloudothyris postovalis Bouc:ot and Johnson, 1968 

Plate 22, figures 6-13 

Cloudothyris postovalis Boucot and Johnson, 1968, p. B19-

B20, pl. 7, figs. 26-42. 

Exterior.-Shell subequally biconvex, pedicle valve 

slightly more convex than brachial valve. Shell outline elongate, elliptical. Lateral margins introverted, 

defining long lateral reentrants which merge posteriorly with planareas. Anterior commissure rectimarginate. Pedicle valve beak short, suberect. Pedicle valve foramen mesothyrid. Deltidial plates, probably present, appear' conjunct, small. Beak ridges 

sharp, define prominent planareas which extend 

width of posterior margin. Maximum width located 

about one-third distance anterior from beak. Concentric growth lines. 

Pedicle valve interior.-Dental lamellae almost 
70 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

obsolete in large specimens due to deposition secondary material in umbonal cavities. Dental lamellae 

short. Hinge teeth bladelike, supported by dental 

lamellae. Muscle field elongate, one-quarter to onefifth as wide, and half as long as valve. Long, narrow diductors posteriorly and laterally surround 

small, elongate, median adductor scar; diductors 

laterally bounded by elongate, pedicle valve adjustor 

impressions. Myophragm bisects posterior part muscle field, extends anteriorly to adductor impression. 

Pedicle callist situated against posterior wall delthyrial cavity. 

Brachial valve interior.-Cardinal plate thick, 

completely sessile, imperforate, supported by crural 

plates almost entirely submerged in secondary material which fills in space under cardinal plate. Anterior portion each crural plate recognizable in small 

specimens. Rising vertically from cardinal plate is 

elongate, terminally bifid cardinal process. Two limbs 

of cardinal process taper to anteriorly directed tips. 

Posterior face each limb indented by slits which 

diverge laterally from base of cardinal process. Lateral sides of slits vertically grooved. Cardinal process of small specimens consists of low, bifid, stumplike structure. Cardinal process covers median half 

cardinal plate, leaving only lateral parts exposed. 

Dental sockets located at posterior base cardinal 

plate, open posteriorly in large specimens, closed 

posteromedially by convergent outer socket ridges 

of small specimens. Dental sockets shallow anteriorly, extend medially well under posterior edge of 

cardinal plate. Muscle field elongate, one-fifth as 

wide and one-quarter to one-fifth as long as valve. 

Posterolateral adductor scars sublunate to elongate, 

deeply impressed posteriorly. Anterior extension 

posterolateral adductor scars bounds ovate, anteromedial adductor scars. Myophragm well developed 

in large specimens, extends posteriorly from anteromedial adductor impression to anterior face of cardinal plate. Valve interior smooth. 

Occurrence.-VSGS locs. 2750-SD, 2814-SD, 

2820-SD, 3238-SD, Brassua Lake quadrangle, Somerset County, Maine. 

Stratigraphic location.-Tomhegan Formation. 

Distribution.----Somerset County, Maine; western 

New York; and possibly northern New Hampshire 

(Boucot and Arndt, 1960). 

Holotype.-USNM 147299 (Boucot and Johnson, 

1968, pl. 7, figs. 28-33) is herein designated the 

holotype. 

Figured specimens.-VSNM 126195, 126210A, 

126208, 126218. 

U nfigured specimens.-USNM 126635-126637. 

Subfamily AMPHIGENIINAE 

Genus AMPHIGENIA Hall, 1867 

Amphigenia parva Clarke, 1907 

Plate 22, figures 14-24 

Exterior.-Shell unequally biconvex, naviculate 

pedicle valve about twice as deep as gently convex 

brachial valve. Shell outline subcircular to elongate, 

elliptical. Maximum width located one-t~ird to o~ehalf distance anterior from beak. Antenor commissure rectimarginate. Lateral margins straight to 

rounded, anterior margin rounded. Hinge line. short, 

rounded. Concentric growth lines, some specimens, 

faint costellae. Beak region characters similar those 

described by Cloud (1942, p. 78, 79) for A. elongata. 

Pedicle valve interior.-Dental lamellae short, 

medially convergent to form spondylium basally supported by median septum. Median septum extends 

to about midlength. Stubby hinge teeth located on 

posterior margins spondylium. Posteriorly spondylium is laterally buttressed by mystrochial plates. 

Excavation for pedicle callist located at posterior 

end delthyrial cavity. Myophragm bisects bottom of 

spondylium. 

Brachial valve interior.-Cardinal plate possesses 

foramen posteriorly, basally supported by pair 

crural plates. Cloud (1942, p. 78) mentioned presence of crural plates converging medially a:boot 

myophragm to form s•truoture resembling cruralium. 

A. curta shows this structure actually formed by 

deposition of secondary material between crural 

plates to raise tube connecting foramen from base 

of shell. This character is one associated with increase in size rather than taxonomic position. Suite 

of specimens of A. parva shows stages having every 

gradation from ones with no secondary material on 

valve floor to those with tube elevated and c~uralium 

appearing to be present. Narrow p·air posterolateral 

adductor impressions laterally border elongate medial adductor impressions, bisected by myophragm 

which extends under cardinal plate. Dental sockets 

laterally directed, posteriorly border cardinal plate. 

Measurements.-Relations between length and 

width of both pedicle and brachial valves are almost random due to mechanical deformation (figs. 

22A, D), plus the fact that the anterior portions of 

some specimens may have been broken off, plus the 

indication that this species is exceptionally variable, 

some specimens having a subcircular outline and 

others being very elongate. Relation between length 

of median septum and width and length of pedicle 

valve is linear with a high degree of dispersion (figs. 

22B, C), which suggests that length and width measurements are very variable due to both biologic and 

mechanical factors. 
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FIGURE 22.-Measurements of Amphigenia, parva Clarke, 1907. Tomhegan Formation, USGS loc. 2750-SD, Brassua Lake quadrangle, Somerset County, 

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72 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

Comparison.-Amphigenia parva is most similar 

to A. elongata, but the greater size reached by many 

specimens of the latter indicates that size may be a 

valid criterion for discrimina.ting between members 

of the two species. From a collection of several 

hundred valves of A. parva, none was observed to 

reach the dimensions common to specimens of A. 

elongata, that is, as much as 10 em in length. A. 

curta shares with A. parva the habit of not reaching 

more than about 3 em maximum length, but A. curta 

has an almost equally biconvex form; brachial valve 

almost as convex as pedicle valve, whereas in A. 

parva brachial valve is relatively flat as contrasted 

with deeply carinate pedicle valve. A. chickasawensis 

has relatively flat valves in contrast to other species 

of the genus. 

Occurrence.-USGS locs. 2750-SD, 2852-SD, 

2820-SD, 2873-SD, 2839-SD, 2814-SD, 2752-SD, 

2723 ?-SD, Brassua Lake quadrangle, Somerset 

County, Maine. 

Stratigraphic location. - Tomhegan Formation 

(Lower Devonian) . 

Distribution.-Somerset County, Maine, and 

northwestern New Hampshire (Boucot and Arndt, 

1960). 

Figured specimens. - USNM 126197, 126196, 

126193,126188,126219,126190,127389. 

Measured specimens.-USNM 126603A-126603AI, 

126604A-126604AP. 

Unmeasured specimens.-USNM 125995-125999, 

126601. 

Family RHIPIDOTHYRIDIDAE 

Subfamily GLOBITHYRIDINAE 

Genus GLOBITHYRIS Cloud, 1942 

Globithyris callida (Clarke, 1907) 

Plate 23, figures 1-5 

Globithyris callida (Clark, 1907), see Cloud, 1942, p. 84, pl. 

11, figs. 5-8, 10-14. 

Exterior.-Shell biconvex, deeply inflated pedicle 

valve more convex than brachial valve. Valve outlines subcircular; brachial valve tending to be transversely elliptical, pedicle valve longitudinally elliptical. Anterior and lateral margins rounded. Anterior 

commissure rectimarginate, crenulate. Pedicle valve 

foramen hypothyrid, deltidial plates medially conjunct. Cardinal margins terebratulid. Pedicle valve 

beak incurved. Costae having round cross section; 

interspaces relatively narrow, V -shaped form. Faint 

growth lines cross concentric ornamentation. 

Twenty-six to forty-three costae, thirty to thirtyeight more common. Maximum width located near 

midlength. 

Pedicle valve interior.-Short, subparallel dental 

lamellae border delthyrial cavity. Muscle field not 

discernible. 

Brachial valve interior.-Discrete hinge plates 

border cruralium formed from basally fused crural 

plates in manner analogous to Amphigenia, forming 

median septum. Cruralium very small, septum extends to about midlength. Dental sockets shallow, 

posteriorly border hinge plates. Brachiophores extend out from anterolateral edges of hinge plates. 

Measurements.-The relation between length and 

30 30~------~--------~------~--------~------~ 

A B (/) 

a: (/) w 

1- a: w w 

1- ~ 

w 20 ...J 

~ ~.. . ... ·. .. ...J .. ·· ...J ... .. ~ ...J I ·:.\ • .: ~ ~ .. ~ r.' 

1-

:r::' (.!) 

1- 10 z 

t!) w 

z ...J 

w ...J 

...J ...J 

w 

10~------~--------+--------+--------~------~ 

:r:: 

(/) 

0 OL-------~--------~------~--------~------~ 

0 10 20 30 0 10 20 30 40 50 

WIDTH, IN MILLIMETERS NUMBER OF PLICATIONS 

FIGURE 23.-Measurements of Globithyris callida (Clarke, 1907). Tomhegan Formation, USGS loc. 2764-SD, Brassua 

Lake quadrangle, Somerset County, Maine. A, width versus length of shells. B, shell length versus number of plications. 
SYSTEMATIC PALEONTOLOGY 73 

width for both Globithyris c.allida and G. diania is 

essentially linear, G. callida shows a much higher 

degree of dispersion due to mechanical deformation 

of the specimens (figs. 23A and 24A). G. callida has 

a larger number of plications, relatively independent 

of size, than G. diania. G. callida has 30-40 (fig. 

23B) with mode about 35, whereas G. diania has 

about 15-30 (fig. 24B) with mode about 23. There is 

an overlap in the number of plications, but the modes 

are very distinct from e·ach other. 

Comparison.-Globithyris callida is distinguished 

from G. diania by latter's coarse ornamentation. 

Ornamentation types overlap so that intermediate 

specimens cannot be assigned specifically unless 

they are part of a population. 

Remarks.-It is notable that both Globithyris and 

the closely related genus Rhenorensselaeria have 

both a coarse-ribbed and a fine-ribbed s.pecies occuring at the same stratigraphic horizon. It is possible that these differences in ornamentation may 

reflect some sexual or environmental rather than 

taxonomic control. 

Occurrence.-VSGS locs. 2764-SD, 2840-SD, 

2736-SD, 2866-SD, 2791-SD, 2757-SD, 2874-SD, 

2716-SD, 2772-SD, 2690-SD, 2828-SD, 3085-SD, 

2714-SD, 3086-SD, 2859-SD, 2835-SD, 2854-SD, 

2727-SD, 2719-SD, 2747-SD, 2744-SD, 2838-SD, 

2713-SD, 2714-SD, 3087-SD, Somerset and Piscataquis Counties, Maine; Globithyris cf. G. callida, 

USGS locs. 2850-SD, 2833-SD, 2863-SD, Somerset 

County, Maine. 

Stratigraphic location. - Tarratine Formation 

(Lower Devonian), and Tomhegan Formation 

(Lower Devonian) . 

Distribution.-N orthern Maine. 

Figured specimens. - USNM 126165, 67778, 

126180. 

M e as u r e d specimens. - USNM 125946A125946BP. 

Unfigured specimens.-VSNM 125947-125972, 

125977. 

Globithyris diania (Clarke, 1907} 

Plate 23, figures 6-13 

Globithyris diania (Clarke, 1907). See Cloud, 1942, p. 83. 

Remarks.-Globithyris diania is identical to G. 

callida in all regards exc·ept number of costae, as 

discussed under G. callida. 

Occurrence.-VSGS locs. 2869-SD, 2713-SD, 

2855-SD, 2867-SD, 2755-SD, 2868-SD, 2851-SD, 

2758-SD, 2759-SD, 2715-SD, 2756-SD, 2763-SD, 

and G. cf. G. diania, 2762-SD, 2755-SD, Somerset 

County, Maine. 

Stratigraphic location. - Tarratine Formation 

(Lower Devonian) and Tomhegan Formation 

(Lowe·r Devonian) . 

Distribution.-N orthern Maine. 

Figured specimens.-VSNM 126164, 126167, 

126182. 

U nfigured specimens.-USNM 125978-125993. 

Measured specimens.-VSNM 125994A125994AK. 

Globithyris sp. 

Remarks.-A few localities have yielded globithyrids too poorly preserved to be assigned 

specifically. 

Occurrence.-VSGS locs. 2878-SD, 2820-SD, 

2754-SD, 2892-SD, 2750-SD, 2752-SD, 2724-SD, 

2818-SD, 2836-SD, 2816-SD, 2817-SD, Somerset 

County, Maine. 

Stratigraphic location. - Tarratine Formation 

(Lower Devonian), and Tomhegan Formation 

(Lower Devonian) . 

Unfigured specimens.-USNM 125973-125976. 

Family MUTATIONELLIDAE Cloud, 1942 

Subfamily MUTATIONELLINAE Cloud, 1942 

Genus MUTA TIONELLA Kozlowski, 1929 

Mutationella parlinensis Bouc:ot, Caster, lves, and Talent, 1963 

Plate 23, figures 14-26 

Mutationella parlinensis, Boucot, Gaster, Ives, and Talent, 

1963, p. 110-113, pl. 34, figs. 6-16; pl. 35, figs, 1-2. 

Exterior.-Unequally biconvex, brachial valve 

gently convex, pedicle valve more inflated. Outline 

subcircular to longi,1Judinally elliptical. Greatest 

width and thickness usually located near midlen:gth. 

Anterior commi1ssure rectimarginate, crenulate. Anterior and lateral margins rounded. Cardinal margins submegathyrid. Pedicle foramen s.ubmesothyrid. 

Large shells possess short p·lanareas. Deltidial 

plates discrete. Pedicle valve beak er.e.ct to suberect 

in large specimens, tends to become slightly incurved 

over brachial valve. Shell punctate. Costellae increase in width peripherally. Costellae have broad, 

rounded cross sections separated by narrow, Vshaped inters paces. Usually 40-60 costellae on each 

valve. 

Pedicle valve interior.-Shell thin in umbonal 

region, no thickening except in delthyrial cavity of 

large specimens. Dental lamellae short, thin. Muscle 

field indistinct, elongate in form, extends about onethird distance to anterior margin. Consists of narrow, median diductor laterally bounded by elongate 

lateral diductor impressions. Posterior portion delthyrial cavity occupied by pedicle callist. Pedicle 

foramen much narrower than chamber occupied by 

pedicle oallist. Hinge teeth stubby, basally supported 

by dental lamellae. Interior crenulated by impress 
7 4 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

30 

A 

(/) 

a: 

w 

1-

w 20 

~ 

...J 

...J - ~ 

~ 

:£ 10 

1-

0 

~ 

0 

0 10 20 30 40 

LENGTH, IN MILLIMETERS 

30 

c 

(/) 

z 

0 

1- 20 <( 

(.) 

...J 

a.. 

LL 

0 

a: 

w 

a::J 10 ~ 

:J 

z 

0~------~--------~------~ 

0 10 20 30 

SHELL WIDTH, IN MILLIMETERS 

external ornamentation except in umbonal region, 

which tends to be smooth. 

Brachial valve interior .-Discrete hinge plates. A 

few specimens possess narrow band joining anterior 

portions of hinge plates. In majority of specimens 

narrow band not present, because it broke during 

burial or because it was never formed. Dental sockets elongate, laterally directed; closed over posteromedially by outer socket ridges but widen laterally 

and are free. Muscle field weakly impress.ed in most 

specimens, ellipsoidal outline, one-fifth as wide and 

one-third as long as valve. Large, ovate, lateral adductors enclose pair narrow, median adductors. 

Median adductors widen rapidly at anterior end of 

muscle field. Muscle field bisected by myophragm. 

Measurements.-The relation between length and 

width of brachial valves is linear, with a low degree 

30 

B 

(/) 

z 

0 

1- 20 

<( 

(.) 

...J 

a.. 

LL 

0 

a: 

w 10 a::J 

~ 

:J 

z 

0 

0 10 20 30 40 

SHELL LENGTH, IN MILLIMETERS 

FIGURE 24.-Measurements of Globithyris diania (Clarke, 

1907). Tomhegan Formation, USGS loc. 2869-SD, Brassua Lake quadrangle, Somerset County, Maine. A, length 

versus width of shells. B, length of shell versus number 

of plications. C, width of shell versus number of plications. 

of dispersion (fig. 25A). Number of plications increases with increase in size, with a range of 35-56 

recorded (figs. 25B, C). Increase in number of plicationa is linear, with a high degree of dispersion. 

Comparison.-M. parlinensis is closely allied 

morp·hologically to the type species in all regards 

except that the former attains dimensions about 

three times those in the latter. Large specim-ens of 

M. parlinensis have a more carinate pedicle valve 

than do large specimens of M. podolica, but this may 

be a function of difference in size. Curvature of 

beak is similar to that in M. podolica and is not 

strongly incurved as in Cloudella stewarti. This 

species possesses short dental lamellae, as does the 

type species. Cardinalia in all respects are similar 

to those of the type species, even in evanescent character of the band connecting the hinge plates. 
(/) 

a: 

w 30 1-

w B ~ 

_J 

_J 

~ 

z 20 I. 

1-

(!) 

z 

w 

_J 

w 

> 10 _J 

<( 

> 

_J 

~ 

I 

() 

<( 

a: 00 CXl 

(/) 

a: 

w 30 

1-

w c ~ 

::i 

_J 

~ 

z 20 

"I 

1-

0 

~ 

w 

> 

_J 10 

<( 

> 

_J 

<( 

I 

() 

<( 

a: 00 CXl 

(/) 

a: 

SYSTEMATIC PALEONTOLOGY 

~ 30~------~--------~---------, 

~ A 

_J 

_J 

~ 

z 

I 

1-

(!) 

z 

w 

_J 

w 

~ 10~---------J'---------+--------I 

<( 

> 

_J 

<( 

I 

() 

<( QL-------~-------~-------~ 

~ 0 10 20 30 

BRACHIAL VALVE WIDTH, IN MILLIMETERS 

10 20 30 40 

NUMBER OF PLICATIONS 

10 20 30 40 

NUMBER OF PLICATIONS 

50 60 

50 60 

FIGURE 25.-Measurements of Mutationella parlinensis Boueot, Caster, lves, and 

Talent, 1963. Lower sandstone of Tarratine Formation, USGS loc. 2718-SD, 

Long Pond quadrangle, Somerset County, Maine. 

75 
76 EARLY PALEOZOIC BRACHIOPODS OF THE MOOSE RIVER SYNCLINORIUM, MAINE 

Weakly impressed musculature is similar to that 

of the type species, as is the thin shell in umbonal 

region of the pedicle valve. 

M. parlinensis closely resembles uTrigeria" gaudryi Hall and Clarke, 1893 (non Oehlert, 1877) 

from Ridgeley Sandstone near Cumberland, Md. No 

specimens of "T." gaudryi Hall and Clarke (non 

Oehlert) were available for study, but plaster casts 

of figured specimens were studied. M. barroisi has 

fewer costellae than M. parlinensis. 

M. parlinensis is similar internally and externally 

to Mutationella falklandica (Clarke, 1913) except 

that the latter has relatively coarser costae. 

uRensselaeria" circularis Schuchert, 1913 may be 

identical (as suggested by Cloud, 1942, p. 83) with 

uTrigeria" gaudryi Hall and Clark (non Oehlert) 

but lack of well-preserved material does not permit 

solution of the problem. uR." circularis was assigned 

by Cloud (1942, p. 83) to Globithyris, but this assignment is untenable owing to the absence of 

crural plates or a median septum in the brachial 

valve of the former. A myophragm is present in 

the brachial valve of "R.'' circularis, as in Mutationella, and hinge plates appear to be discrete. It 

is suggested that "R." circularis be assigned questionably to Mutationella p·ending discovery of more 

adequate specimens. 

Occurence and stratigraphic loc.a.tion.-VSGS locs. 

2718-SD, 2691-SD, 2719-SD, 2717-SD, 2721-SD, 

2731-SD, 2735-SD, 2720-SD, 2765-SD, 2749-SD, 

2777-SD, 2795-SD, 2793-SD, 2776-SD, 2767-SD, 

2722-SD, 2861-SD, 2727-SD, 2732-SD, 2831-SD, 

2890-SD, 2875-SD, 2824-SD, 2865-SD, 2823-SD, 

2783-SD, 2821-SD, 2834-SD, 2847-SD, 2862-SD, 

3088-SD, 3090-SD, 3225-SD, 2832-SD; Mutationella cf. M. parlinensis from USGS locs. 2819-SD, 

2825-SD, 2747-SD, Somerset County, Maine, in the 

Tarratine Formation (Lower Devonian) and questionably the Kineo m·ember of the Tomhegan Formation (Lower Devonian). 

Distribution.-Somers·et County, Maine, and possibly Cumberland, Md., if "Rensselaeria" circularis 

and uTrigeria" gaudryi belong to this genus and 

species. A single poorly preserved specimen from 

the· Perce limestone at Perce, Queibec, in the collections of the Museum of Comparative Zoology, 

Harvard Univ., Cambridge, Mass., resembles this 

species. Strata of similar age in Piscataquis and 

Penobscot Goulllties, Maine, have not, as yet, produced specimens of Mutationella, but Cloudella (a 

closely related genus) occurs in the area of Ma.tagamon Dam, Penobscot County, and M endatkyris (another closely related genus) occurs in the Presque 

Isle are·a, Aroostock County, M·aine. 

H olotype.-UNSM 126178. 

Figured specimens.-USNM 126168, 126185, 

126186, 126166, 126173, 126171. 

Measured specimens.-USNM 126671 A-V. 

Unmeasured specimens.-USNM 126638, 126674,. 

REFERENCES CITED 

Albee, A. L., and Boudette, E. L., 1972, Geology of the Attean 

quadrangle, Somerset County, Maine: U.S. Geol. Survey 

Bull. 1297, 110 p. 

Amsden, T. W., 1951, Brachiopods of the Henryhouse Formation (Silurian) of Oklahoma: Jour. Paleontology, v. 25, 

no. 1, p. 69-96. 

Berdan, J. M., 1963, Eccentricosta, a new Upper Silurian 

brachiopod genus: Jour. Paleontology, v. 37, no. 1, p. 

245-256. 

Berry, W. B. N., and Boucot, A. J .. 1970, Correlation of the 

North American Silurian rocks: Geol. Soc. America 

Spec. Paper 102, 289 p. 

Billings, Elkanah, 1874, Paleozoic fossils, v. 2, pt. 1: Canada 

Geol. Survey, 144 p., pls. 1-10. 

Boucot, A. J., 1959a, Early Devonian Ambocoeliinae (Brachiopoda): Jour. Paleontology, v. 33, no. 1, p. 16-24, pls. 

1, 2. 

-- 1959b, Brachiopods of the Lower Devonian rocks at 

Highland Mills, New York: Jour. Paleontology, v. 33, 

no. 5, p. 727-769. 

-- 1961, Stratigraphy of the Moose River synclinorium, 

Maine: U.S. Geol. Survey Bull. 1111-E, p. 153-188. 

-- 1969, Geology of the Moose River and Roach River 

Synclinoria, northwestern Maine; with contributions by 

E. W. Heath: Maine Geol. Survey Bull. no. 21, 117 p. 

Boucot, A. J., and Amsden, T. W., 1964, Chonostrophiella, a 

new genus of chonostrophid brachiopod: Jour. Paleontology, v. 38, no. 5, p. 881-884, pl. 141. 

Boucot, A. J., and Arndt, Robert, 1960, Fossils of the Littleton Formation (Lower Devonian) of New Hampshire: 

U.S. Geol. Surv. Prof. Paper 334-B, p, 41-51. 

Boucot, A. J., Caster, K. E., Ives, David, and Talent, J. A., 

1963, Relationships of a new Lower Devonian terebratuloid (Brachiopoda) from Antarctica: Bull. Am. Paleontology, v. 46, no. 207, p. 77-151, pis. 16-41. 

Boucot, A. J., and Harper, C. W., 1968, Silurian to lower 

Middle Devonian Chonetacea: Jour. Paleontology, v. 42, 

no. 1, p. 143-176, pls. 27-30. 

Boucot, A. J., and Johnson, J. G., 1967a, Species and distribution of Coelospira (Brachiopoda): Jour. Paleontology, 

v. 41, no. 5, p. 1226-1241, pis. 163-166. 

-- 1967b, Paleogeography and correlation of Appalachian Province Lower Devonian sedimentary roeks: 

Tulsa Geol. Soc. Digest, v. 35, p. 35-87, 2 pis. 

-- 1968, Brachiopods of the Bois Blanc Formation in 

New York: U.S. Geol. Survey Prof. Paper 584-B, 27 p. 

Boucot, A. J., Johnson, J. G., and Staton, R. D., 1964, On 

some atrypoid, retzioid and athyridoid Brachiopoda: 

Jour. Paleontology, v. 38, no. 5, p. 805-822. 

Boucot, A. J., Johnson, J. G., and Talent, J. A., 1969, Early 

Devonian brachiopod zoogeography: Geol. Soc. America 

Spec. Paper 119, 106 p. 

Boucot, A. J ., and Y ochelson, E. L., 1966, Paleozoic Gastropoda from the Moos·e River synclinorium, northern 

Maine: U.S. Geol. Survey Prof. Paper 503-A, p. A1-

A20, pis. 1-3. 
REFERENCES CITED 77 

Caster, K. E., 1939, A Devonian fauna from Colombia: Bull. 

Am. Paleontology, v. 24, no. 83, p. 1-218. 

Clarke, J. M., 1900, The Oriskany fauna of Becraft Mountain, Columbia County, N.Y.: New York State Mus. 

Mem. 3, v. 3, 101 p. 

--- 1907, Some new Devonic fossils: New York State 

Mus. Bull. 107, p. 153-291. 

--- 1909, Early Devonic history of New York and eastern North America: New York State Mus. Mem. 9, pt. 

2, 250 p., 34 pls. 

Cloud, P. E., Jr., 1942, Ter·ebratuloid Brachiopoda of the 

Silurian and Devonian: Geol. Soc. America Spec. Paper 

38, 182 p., 26 pls. 

Cooper, G. A., 1956, Chazyan and related brachiopods: Smithsonian Misc. Coli., v. 127, 1024 p. 

Dunbar, C. 0., 1919, Stratigraphy and correlation of the 

Devonian of western Tennessee: Tennessee State Geol. 

Survey, Bull. 21, 127 p. 

Foerste, A. F., 1903, Silurian and Devonian limestones cf 

western Tennessee: Jour. Geology, v. 11, p. 554-583, 

679-715. 

--- 1909, Fossils from the Silurian formations of Tennessee, Indiana, and Kentucky: Denison Univ. Sci. Lab. 

Bull. 14, p. 61-116. 

Goldring, Winifred, 1933, A new species of crinoid from the 

Devonian (Oriskany) of Maine: Portland Soc. Nat. 

History Proc., v. 4, p. 153-155, pls. 3, 4. 

Hall, James, 1863, Contributions to palaeontology: New 

York State Cabinet of Natural History 16th annual 

report, p. 3-226. 

Hall, James, and Clarke, J. M., 1894, An introduction to the 

study of the genera of Palaeozoic Brachiopoda: New 

York Geol. Survey, Palaeontology, v. 8, pt. 2; 1893, 

prepr., p. 1-317; 1894, 394 p., pls. 21-84 [1895]. 

Lesperance, P. J., 1968, Ordovician and Silurian trilobite 

faunas of the White Head Formation, Perce region, 

Quebec: Jour. Paleontology, v. 42, no. 3, p. 811-826. 

Neuman, R. B., 1968, Paleogeographic implications of Ordovician shelly fossils in the Magog belt of the northern 

Appalachian region, Chap. 3 in Zen, E-an, and others, 

eds., Studies of Appalachian geology, northern and 

maritime: New York and London, Interscience Publishers, p. 35-48. 

Oliver, W. A., Jr., 1960, Devonian rugose corals from northern Maine: U.S. Geol. Survey Bull. 1111-A, p. 1-23, 

pis. 1-5. 

--- 1962, Silurian rugose corals from the Lake Temiscouata area, Quebec: U.S. Geol. Survey Prof. Paper 430-B, 

p. 11-19, pls. 5-8 [1963]. 

--- 1967, Succession of rugose coral faunas in the Lower 

and Middle Devonian of eastern North America, in 

Internat. Symposium on the Devonian System, Calgary, 

Alberta, 1967 [Proc.] V. 2: Calgary, Alberta, Alberta 

Soc. Petroleum Geologists, p. 733-744 [1968]. 

Pirsson, L. V., and Schuchert, Charles, 1914, Note on the 

occurrence of the Oriskany Formation on Parlin Stream, 

Maine: Am. Jour. Sci., Ser. 4, v. 37, p. 221-224. 

Schuchert, Charles, and Cooper, G. A., 1931, Synopsis of the 

brachiopod genera of the suborders Orthoidea and 

Pentameroidea, with notes on the Telotremata: Am. 

Jour. Sci., Ser. 5, v. 22, p. 241-251. 

Stumm, E. C., 1962, Silurian corals from the Moose River 

synclinorium, Maine: U.S. Geol. Survey Prof. Paper 

430-A, p. 1-9, pls. 1-4. 

Walmsley, V. G., Boucot, A. J., and Harper, C. W., 1969, 

Silurian and lower Devonian salopinid brachiopods: 

Jour. Paleontology, v. 43, no. 2, p. 492-516. 

Weller, S., 1903, The Paleozoic faunas: New Jersey Geol. 

Survey, Pal. 3, 462 p. 

Whittington, H. B., and Campbell, K. S. W., 1967, Silicified 

Silurian trilobites from Maine: Harvard Univ., Mus. 

Comp. Zoology Bull., v. 135, p. 447-483, 19 pls. 

Williams, Alwyn, 1951, Llandovery brachiopods from Wales 

with special reference to the Llandovery District: Geol. 

Soc. London Quart. Jour., v. 107, pt. 1, no. 425, p. 85-

136. 

--- 1953, North American and European stropheodontids: 

their morphology and systematics: Geol. Soc. America 

Mem. 56, 67 p. 

Williams, Alwyn, and others, 1965, Treatise on invertebrate 

paleontology, Part H, Brachiopoda, V. 1-2: New York, 

Geol. Soc. America (and U niv. Kansas Press) , 927 p. 

Williams, H. S., and Breger, C. L., 1916, The fauna of the 

Chapman sandstone of Maine: U.S. Geol. Survey Prof. 

Pap.er 89, 347 p., 27 pis. 

Woodard, H. H., 1951, Report on the geology of a portion 

of the Spencer Lake area, Maine: Maine Geol. Survey 

Rept. State Geologist 1949-50, p. 68-77. 

Page 

A 

acinum, Rhynchonella ________________ _ 30 

30 

30 

41 

acinus, Diabolirhynchia ----------------

Rhychonella -------------------

Acrospirifer 

angularis ----------------- 43 

atla,nticus ----------- 3, 46; pl. 17 

hartleyi ------------------ 43 

intermedius -------------- 47 

murchisoni ------ 41, 43, 47; pl. 16 

olssoni ------------------- 51 

sp. 1 ------------------47; pl. 17 

sp. 2 ------------------ 48; pl. 18 

aequiradiata, Atrypa ----------------- 66 

Age, faunas -------------------------- 1 

Hardwood Mountain Formation ___ 2 

Little Big Wood Pond beds ------- 2 

alsa, Discomyorthis ------------------- 13 

Rhipidomella ------- ___ ___ _ ____ _ _ 13 

altisulcata, Ancillotoechia ----------- 30; pl. 12 

Ambocoeliidae ___ ---------- _ ___ ___ _____ 62 

Ambocoeliinae ------------------------ 62 

Amphigenia ------------------------ 3, 70, 72 

chickasawensis ----------- 72 

curta --------------------- 72 

elongata ------------------ 70 

parva ----------------- 70; pl. 22 

Amphigeniinae ------------------------ 70 

Amphistrophia ------------------------ 1 

funiculata ------------- 1, 2 

ampla, Strophonella ------------------- 23 

Ancillotoechia ------------------------- 30 

altisulcata ----------- 30; pl. 12 

bialveata ---------------- 30 

haraganensis ------------ 30 

sp ------------------- 30; pl. 12 

angularis, Acrospirifer ---------------- 43 

angustiplicata zaleszczykiensis, H owellella 41 

Anopliidae _ -- _ __ _ _ _ __ _ ___ __ __ _ _ _ _ ___ __ 25 

Anoplothecidae 38 

Anopliinae ___ ------------------- ___ _ _ 25 

Anthyrididae ------------------------- 65 

Anthyridinae ------------------- __ _ ___ 65 

Antispirifer --------------------------- 50 

harroldi --------------- 50; pl. 18 

Appalachian forms -------------------- 3 

Appalachian ostracode faunda --------- 3 arctostriata, Atrypa ________________ 36; pl. 14 

arcuaria, lsorthis --------------------- 10 

arcuata, Eodevonaria ------------ 3, 27; pl. 11 

Aroostook County --------------------- 3 

atlanticus, Acrospirifer ---------- 3, 46; pl. 17 

Atrypa ------------------------------- 36 

aequiradiata ------------------ 66 a,rctostriata _________________ 36; pl. 14 

reticularis ---------------- 2, 36; pl. 15 

reticularis s.l ----------------- 37 

tennesseenis ---------------- 36; pl. 14 

Atrypidae ----------------- ___ -------- 36 A trypinae ___________________________ _ 36 

avus, Nanothyris subglobosa ----------- 66 

B 

Baltic-type fauna ---------------------

barroisi, Mutationella ------------------ 76 

INDEX 

[Italic page numbers indicate major references] 

Page 

Beachia ------------------------------ 3, 69 

suessana --------------------- 69 

thunii ------------- 66, 69; pls. 21,22 

Bear Pond Limestone Member --------- 3 

Beck Pond ---------------------------- 3 

Beck Pond Limestone ----------------- 3 

beckensis, Sieberella ---------------- 20; pl. 6 

becraftensis, Schuchertella ----------- 24; pl. 9 

Berdan, J. M., cited ------------------ 2 

bialveata, .4ncillotoechia --------------- 30 

Rhynchonella ---------------- 30 

bidentata, Rhynchonella --------------- 30 

blainvillei, Protoleptostrophia _______ 22; pl. 8 

brownsportensis, Orthostrophia ------- 4; pl. 1 

c 

callida, Globithyris ------------- 72, 73; pl. 23 

Camarotoechia ------------------------ 30 

canadensis, Dawsonelloides ______ 26; pls. 10,11 

Centronellidae _____________ ----------- 65 

Charionoide3 -------------------------- 64 

doris -------------- 3, 64; pl. 20 

chickasawensis, Amphigenia ----------- 72 Chonetidae _ __ _ __ __ _ __ __ _ __ _ __ _ __ _ __ __ 25 

Chonetinae _________________ ---------- 25 

Chonostrophiella ---------------------- 1, 28 

complanata ____ 28; pls. 11, 12 

Chonostrophiellinae ------------------- 28 

circularis, Rensselaeria ---------------- 76 

cliftonensis, Dalejina ------------------ 16 

Cloud, Preston E., Jr., cited ----------- 1 

Cloudella ----------------------------- 76 

stewarti -------------------- 74 Cloudothyris _ __ _ ___ _ __ _ __ _ __ __ _ __ _ __ __ 69 

postovalis ------------- 69; pl. 22 Coelospira ___________________________ 1, 2, 38 

sp ---------------------- 38; pl. 15 

Coelospirinae ------------------------- 38 

coeymanensis, Gy]J'idula ---------------- 19 

complanata, Chonostrophiella ___ 28; pls. 11, 12 

Conodonts, Little Big Wood Pond ------ 2 

cooperi, Plicoplasia -------------------- 63 

Coral analysis, Oliver, W. A., Jr. ------ 4 

Corals, Little Big Wood Pond ---------- 2 

Costellirostra ------------------------- 34 

sp ------------------- 34; pl. 14 

Costellispirifer ------------------------ 51 

perimele ------------51; pl. 18 

Costispirifer -------------------------- 3, 61 

sp -------------------- 61; pl. 18 

Costispiriferinae ---------------------- 61 

crassa, Nanothyris subglobosa --------- 66 

cumberlandiae, Spirifer --------------- 60 

Cupularostrum ------------------------ 29 

macrocosta --------- 29; pl. 12 

recticostatum ---------- 30 

sp ------------------ 30; pl. 12 

curta, Amphigenia -------------------- 72 

cycloptera, Howellella ----------------- 40 

cyclopterus, Howellella ------------- 40; pl. 16 

Cyrtina ------------------------------ 63 

rostrata ------------------- 63; pl. 19 Cyrtinidae - __ --- __ _ __ _ __ _ ___ __ _ __ _ __ _ _ 63 

Cyrtininae ---------------------------- 63 

cyrtinoides, Megakozlowskiella --------- 62 Cyrtoniscus ___ --- _ _ __ _ __ _ _ __ _ __ _ _ _ __ __ 1, 25 

nectus ------------------ 25; pl. 9 

Page 

D 

Dalejina ______________________________ 13, 16 

cliftonensis _ __ _ _ _ __ _ _ __ __ _ __ _ _ 16 

newsomensis ----------------- 16 

subtriangularis --------------- 16 

sp. 1 ---------------------- 16; pl. 3 

sp. 2 ------------------------ 16 

sp --------------------------- 16 

Dalmanellidae ___ --- ___ ----------- ___ __ 9 

Dawsonelloides _________ -- _______ --- __ 1, 3, 26 

canadensis ------- 26; pls. 10, 11 

Delthyrididae _________ ----------- _ __ __ 39 

Delthyridinae ------ ______ ------------- 39 

Delthyris ----------------------------- 39 ( Delthyris) _ _ __ __ _ __ _ _ __ _ __ __ 2 

kozlowskii ---------------- 39; pl. 16 

pegramensis ----------------- 39 

demissa, Stropheodonta -------------- 21; pl. 6 

Devonian, Lower ---------------------- 3 

Diabolirhynchia ----------------------- 30 

acinus ---------------- 30 

diania, Globithyris ----------------- 73; pl. 23 

Dicaelosia ___ -- _- ______ --------- ____ -- 1, 11 

sp ---------------------- 1, 11; pl. 3 

Dicaelosiidae -------------------------- 11 Dinorthidae _______________________ :_ __ 8 

Discomyorthis ---------------------- 12, 13,16 

alsa ___________ -- ___ __ __ 13 

eryna ------------------ 13 

musculosa -------------- 13 

musculosa solaris ___ 12; pls. 3. 4 

oblata ------------------ 12,13 

sp ---------------------- 13,16 

Dolerorthinae ------------------------- 5 Dolerorthis ___ _ ___ __ ___ __ __ __ _____ ____ 2, 5 

hami -------------------- __ 7; pl. 2 

hobbstownensis ----------5, 6; pl. 1 

rustica osiliensis ------------ 7 

sp ------------------------ 7; pl. 2 

s.s. ------------------------ 6 

doris, Charionoides --------------- 3, 64; pl. 20 

Draboviine ---------------------------- 18 

dryope, Rhynchonella ------------------ 29 

duodenarius, Spirifer ------------------ 47 

E 

Early Devonian fauna, Moose River 

synclinorium ------------- 1 

Early Silurian fossils, Limestone Hill __ 

Early Wenlock brachiopods, Limestone 

Hill ---------------------- 1 

Eatonia 34 

medialis ------------------- 34; pl. 14 

sp --------------------------- 35 Eatoniidae ___ - __ _ _ _ __ _ _ __ __ _ __ ___ _ __ _ _ 34 

Ecccntricosta ------------------------ 2, 3, 25 

sp ------------------- 25; pl. 10 

Eitelian age ----------------------- 4 

elongata, Amphigenia ----------------- 70 

engelmanni, Spirifer ------------------ 51 

Eodevonaria -------------------------- 1, 27 

arcuata -------------- 3, 27; pl. 11 

Eospirifer ---------------------------- 2 

Eospiriferidae ------------------------ 39 

Eospiriferinae ------------------------ 39 

eryna, Discomyorthis ------------------ 13 

79 
80 

Page 

Esopus age --------------------------- 8 

European forms ----------------------

Eurythyridinae ----------------------- 69 

excellens, Rhynchonella ---------------- 29 

F 

falklandica, Mutationella 76 

Famine Limestone -------------------- 4 

Faunas, age --------------------------

ftabellites, Leptocoelia -------------- 38; pl. 15 

formosa, Machaeraria ----------------- 85 

funiculata, Amphistrophia ------------- 1, 2 

G 

Gaspe -------------------------------- 8 

gaspensis, Howellella ------------------ 41 

gaudryi, Trigeria --------------------- 76 

Globithyridinae ----------------------- 72 

Globithyris ----------------------3, 72, 78, 76 

callida -------------- 72, 73; pl. 28 

diania ------------------ 73; pl. 28 

sp ------------------------ 73 

Glyptorthinae ------------------------- 7 

Greenfieldia --------------------------- 65 

Gypidula ----------------------------- 2, 19 

coeymanensis ---------------- 19 

sp. 1 --------------------- 19; pl. 5 

sp. 2 ------------------- 19; pls. 5, 6 

Gypidulidae --------------------------- 19 

Gypidulinae 19 

H 

hami, Dolerorthis -------------------

haraganensis, Ancillotoechia -----------

7; pl. 2 

30 

Hardwood Mountain Formation -------- 2 

harroldi, Antispirifer ---------------50; pl. 18 

hartleyi, Acrospirifer ----------------- 48 

Hedeina ------------------------------ 89 

macropleura --------------- 39; pl. 15 

Helderberg age ----------------------- 3 

Helderberg faunas --------------------

Hesperothidae ___ --- ______ ------------ 5 

H esperorth is 5 

Hipparionyx -------------------------- 8, 24 

sp --------------------- 24; pl. 9 

hitchcocki, Salopina ------------------18; pl. 5 

Hobbstown Formation, lower 

conglomerate member ----- 2 

hobbstownensis, Dolerorthis ------- 5; 6; pl. 1 

hodgei, Nanothyris ----------------- 65; pl. 21 

Howellella ---------------------------- 2, 89 

angustiplicata Zaleszczykiensis 41 

cycloptera ------------------ 40 

cyclopterus -------------- 40; pl. 16 

gaspensis ------------------ 41 

mckenzica ------------------ 41 

nerei ---------------------- 41 

tomheganensis ---------- 40; pl. 16 

sp ---------------------- 39; pl. 16 

intermedius, Acrospirifer -------------- 47 

Introduction -------------------------- 1 

Isorthinae ---------------------------- 10 

lsorthis 10 

arcuaria ---------------------- 10 

perelegans --------------- 10,11; pl. 8 

sp. 1 ------------------- 10, 11; pl. 2 

sp. 2 -----------------------10; pl. 2 

sp. 3 ----------------------- 10; pl. 3 

K 

Kennebec Formation ------------------- 3 

Kineo Rhyolite ----------------------- 3 

INDEX 

Page 

Kirkidium knighti -------------------- 2 

knighti, Kirkidium -------------------- 2 

Kozlowskiellina ----------------------- 62 

Kozlowskiellinae ---------------------- 62 

kozlowskii, Delthyris --------------- 39; pl. 16 

L 

lata, Meristella -------------------- 64; pl. 20 

Late Llandovery brachiopods, 

Leptaena 

Limestone Hill ------------ 1 

20 

rhomboidalis -------------- 20; pl. 6 

Leptaenidae -------------------------- 20 

Leptaenisca -------------------------- 25 

sp ---------------------- 25; pl. 9 

Leptaenoideinae ---------------------- 25 

Leptocoelia --------------------------- 38 

ftabellites -------------- 38; pl. 15 

Leptocoeliidae ------------------------ 88 

Leptostrophia ------------------------ 21, 22 

Levenea 

magnifica ------------- 21; pl. 7 

sp ------------------- 22; pl. 7 

11 

subcarinata ------------------ 11 

sp -------------------------11; pl. 8 

Limbinaria muricata ------------------ 2 

Limestone Hill, Early Silurian fossils-- 1, 3 

Lissatrypa 

early Wenlock 

brachiopods ---------------

late Llandovery 

brachiopods --------------- 1 

2,37 

sp --------------------- 37; pl. 15 

Lissatrypidae ------------------------- 37 

Little Big Wood Pond ----------------- 2 

Lobster Lake Formation -------------- 2 

lucia, Orthis -------------------------- 17 

Ludlow age --------------------------- 2 

M 

Machaeraria 35 

formosa ------------------ 35 

mainensis ------------- 35; pl. 14 

macra, Mucrospirifer --------------- 60; pl. 18 

macrocosta, Cupularostrum --------- 29; pl. 12 

macropleura, Hcdeina -------------- 39; pl. 15 

magnifica, Leptostrophia ----------- 21; pl. 7 

mainensis, Machaeraris ------------- 35; pl. 14 

mckenzica, Howellella ----------------- 41 

medialis, Eatonia ------------------- 34; pl. 14 

Megakozlowskiella --------------------- 62 

cyrtinoides --------- 62 

sp ____ ----------- 62; pl. 19 

Megalanteris thunei ------------------- 69 

Meganteris ---------------------------- 69 

Meifodia ------------------------------ 37 

Mendathyris -------------------------- 76 

Merista 63 

tennesseensis --------------- 63; pl. 20 

Meristella ----------------------------- 64 

lata --------------------- 64; pl. 20 

sp -------------------------- 64 

Meristellidae -------------------------- 63 

Meristel!inae -------------------------- 64 

Meristinae 

Metaplasia 

63 

------------------------- 1, 62, 63 

minuta ----------------- 62; pl. 19 

paucicostata ------------- 62; pl. 19 

pyxidata ------------------ 62 

minuta, Metaplasia ---------------- 62; pl. 29 

Mont Wissick Formation ------------- 2 

Moose River synclinorium, purpose 

geologic study ------------

Mucrospirifer ------------------------- 60 

macra -------------- 60; pl. 18 

Mucrospiriferinae --------------------- 60 

murchisoni, Acrospirifer ----- 41, 43, 47; pl. 16 

muricata, Limbinaria -----------------

musculosa, Discomyorthis -------------

Rhipidomella --------------

Page 

2 

13 

13 

solaris, Discomyorthis ___ 12; pis. 3, 4 

muta.balis, Nanothyris ---------------- 66 

Mutationella ------------------------- 1, 3, 73 

barroisi ----------------- 76 

community -------------- 3 

falklandica --------------- 76 

parlinensis -------- 73, 76; pl. 23 

podolica ____ ------------- 74 

Mutationellidae 

M'utatione!linae 

73 

73 

N 

Nanospira 37 

sp ---------------------- 37; pl. 15 

Nanothyris ------------------------ 65, 66,69 

hodgei ----------------- 65; pl. 21 

mutabilis ----------------- 66 

reesidei ------------------- 66 

subglobosa ------------- 66; pl. 21 

subglobosa avus ----------- 66 

s1tbglobosa crassa --------- 66 

nectus, Cyrtoniscus ----------------- 25; pl. 9 

nerei, Howellella ---------------------- 41 

New Brunswick ---------------------- 3 

ncwsomensis, Dalejina ---------------- 16 

Nucleospira --------------------------- 65 

sp -------------------- 65; pl. 20 

Nucleospiridae ------------------------ 65 

0 

oblata, Discomyorthis ----------------

Old World genus ----~---------------­

Old World province ------------------

Oliver, W. A., Jr., cor11.l analysis -----

olssoni, Acrospirifer ------------------

Onondaga age ·-----------------------

Ordovician age -----------------------

Late -------------------

Middle ----------------

Ordovician trilobites, Late ------------

Oriskany age -------------------------- Orthambonites _________________ ------

12, 13 

3 

3, 4 

4 

51 

4 

3 

3 

3 

3 

3, 4 

5 

Orthidae 

Orthinae 

sp ----------------- 1, 5; pl. 1 

4 

5 

Orthis lucia -------------------------- 17 

Orthoid, unidentified --------------- 11; pl. 3 

Orthostrophia --~---------------------- 4 

b1'ownsportensis _ _ _ _ _ _ _ 4; pl. 1 

strophomcnoides ------ 4; pl. 1 

Orthostrophinae -------------------·-- 4 

osiliensis, Dolerorthis rustica ---------- 7 

Ostracodes, Little Big Wood Pond ----- 2 

p 

Paleonto!ogy, systematic -------------- 4 

Parker Bog Formation --------------- 3 

parlinensis, Mutationella -------- 73, 76; pl. 23 

parva, A1nphigenia ---------------- 70, pl. 22 

paucicostata, Metaplasia ----------- 62; pl. 19 

pegramensis, Delthyris --------------- 39 

Reticularia -------------- 39 

Penobscot County -------------------- 3 

Pentameridae 20 

Pentamerinae ------------------------- 20 

Pentameroides ------------------------ 20 

Pentamerus sp ------------------ 1, 20; pl. 6 

perelegans, lsorthis ------------- 10,11; pl. 3 

perimele, Costellispirifer ---------- 51; pl. 18 

Spirifer --------------------- 51 

pirssonae, Spirifer ------------------- 51 

planoconvexa, Platyorthis ---------- 16; pl. 4 
Platyorthinae -------------------------

Platyorthis ___ ------------------------

Page 

16 

13,16 

planoconvexa ----------- 16; pl. 4 

Plectambonitidae 20 

Plectambonitina.e 20 ---------------------

plicata, Plicoplasia --------------- 63; pl. 19 

Plicoplasia ---------------------------- 1, 63 

cooperi ------------------- 63 

plicata ---------------- 63; pl. 19 

podolica, Mutationella ----------------- 74 

postovalis, Cloudothyris ------------ 69; pl. 22 

Pridoli age --------------------- 2, 3 

Protathyris _________ -------- 65 

Protathyris sp -------------------- 65; pl. 20 

Protoleptostrophia ---------------- 22 

blainvillei -------- 22; pl. 8 

sp -------- 22, 23; pls. 7, 8 

Provinciality -------------------------- 3 

Ptychopleurell(!, -------------·--------- 2, 7, 8 

sp ------------------- 7; pl. 2 

s.s -------------------- 8 

punctulifera, Strophonella ---------- 23; pl. 8 

Purpose, geologic study Moose River 

synclinorium -------------

pyxidata, Metaplasia ------------------ 62 

Q, R 

Quebec _ -- ___ - ------------------------ 3 

recticostatum, Cupularostrum --------- 30 

reesidei, Nanothyris ------------------ 66 

References cited ---------------------- 76 

Rensselaeria -------------------------- 3, 66 

circttlaris ---------------- 76 

sp ------------------- 66; pl. 21 

s.s ---------------------- 66 

Rensselaeriinae ----------------------- 65 

Resserella ---------------------------- 2, 9 

sp -------------------- 9, 10; pl. 2 

Reticutaria pegramensis --------------- 39 

reticularis, Atrypa ------------- 2, 36; pl. 15 

Atrypa s.l ----------------- 37 

Rhenish community ------------------

Rhenorensselaeria --------------------- 73 

Rhipidomella alsa --------------------- 13 

mttsculosa ---------------- 13 

Rhipidomellidae --------------------- 12, 16 

Rhipidomellinae ___ - ------ __ - ---------- 12 

Rhipidothyrididae ___ --- ______ --------- 72 

rhomboidalis, Leptaena -------------- 20; pl. 6 

Rhynchonella acinum ----------------- 30· 

INDEX 

Rhynchonella acinus --------------

bialveata ----------------

bidentatx --------------

Page 

30 

30 

30 

dryope ----------------- 29 

excellens ---------------- 29 

Rhynchotrematidae -------------------- 35 

roemeri, Sieberella -------------------- 20 

rostrata, Cyrtina ------------------- 63; pl. 19 

rustica osiliensis, Dolerorthis ---------- 7 

s 

Saint George, Quebec -----------------

Sally Mountain ----------------------

4 

2 

Salopina ----------------------------- 1, 18 

hitchcocki --------·-------- 18; pl. 5 

Schizophoria striatula 13 

sp ---------------------- 13 

Schizophoriidae --------------·--------- 18 

Schizoramma ------------------------ 4; pl. 1 

subplicata --------------- 4 

Schoharie age 

Schuchertella 

3, 4 

24 

becraftensis ---·-------- 24; pl. 9 

sp -------------------- 24; pl. 9 

Schuchertellidae ---------------------- 24 

Schuchertellinae ----------------------

Seboomook Formation ----------------

Sieberella ---- ____________ -------------

24 

3 

20 

beckensis ---------------- 20; pl. 6 

roemeri -------------------- 20 

sieberi --------------------- 20 

sieberi, Sieberella -----------·--------- 20 

Siluri:m age ------------------------ 2, 3 

solaris, Discomyorthis musculosa __ 12; pls. 3, 4 

Somerset County --------------------- 3 

Sowerbyites sp ------------------ 1, 20; pl. 6 

Spencer Mountain outlier ------------ 2 

Sphaerirhynchia ---------------------- 31 sp. I _________ 31; pls. 12, 13 

sp. 2 _____________ 32; pl. 13 

sp. 3 -------------- 33; pl. 13 

sp ---------------- 33; pl. 13 

Spinoplasia _ ---- ___ ------------------- 3 

Spirifer cumberlandiae --------------- 60 

duodenarius ----------------- 47 

engelmanni ---- ________ - ----- 51 

perimele --------------------- 51 

pirssonae -------------------- 51 

worthenanus ----------------- 51 

stewarti, Cloudella ------------------- 74 

Stratton quadrangle ------------------

striatula, Schizophoria ----------------

Stropheodonta -------------------

81 

Page 

1 

13 

21 

demissa ------------- 21; pl. 6 

sp ----------------- 21; pl. 6 

s. s -------------------- 21 

Stropheodontidae -------------

Stropheodontinae ---------------------

Strophomenidae ----------------------

strophomenoides, Orthostrophia ------ 4; pl. 1 

21 

21 

25 

Strophonella ------ _ ----------- 23 

ampla ------------------ 23 

punctulifera ----------- 23; pl. 8 

subcarinata, Levenea ----------------- 11 

subglobosa, Nanothyris ------------ 66; pl. 21 

avus, Nanothyris --------- 66 

crassa, Nanothyris -------- 66 

subplicata, Schizoramma -------------- 4 

subtriangularis, Dalejina ------------- 16 

sttessana, Beachia --------------------

sulcata, Sulcatina --------------------

Sulcatina _ ----------------------------

sulcata 

69 

34 

2, 33 

34 

tennesseenis ---------------- 34 

sp ---------------------- 33; pl. 13 

Systematic Paleontology -------------- 4 

T 

Tarratine Formll.tion ----------------- 3 

tennesseenis, Atrypa -------------- 36; pl. 14 

Mcrista ______________ 63; pl. 20 

Sulcatina ---------------- 34 

thunei, Megalanteris ------------------ 69 

thunii, Beachia ------------ 66, 69; pis. 21, 22 

Tomhegan Formation ---------------- 3 

tomheganensis, Howellella --------- 40; pl. 16 

Tono!oway Limestone ----------------

Trigeria gaudryi ---------------------

Trigonirhynchiiche --------------------

u. v. w. z 

Uncinulidae 

2 

76 

29 

31 

Valcourea ---------------------------- 8 

sp --------------------- 1, 8: pl. 2 

Wenlock age, late ------------------- 2 

worthenanus, Spirifer ---------------- 51 

zaleszczykiensis, H owcllclla 

angustiplicata ------------ 41 

PLATES 1-23 

[Contact photographs of the plates in this report are available, at cost, from U.S. 

Geological Survey Library, Federal Center, Denver, Colorado 80225] 
PLATE 1 

FIGURES 1-5. Orthostrophia cf. 0. brownsportensis Amsden. 19·49 (p. 4). 

Hardwood Mountain Formation. USGS loc. 4843-SD, Attean quadrangle, Somerset County, Maine. X 3. 

1. Impression of interior of pedicle valve. Note tripartite form of muscle field with concentric striae, 

obsolescent nature of dental lamellae, presence of umbonal fold and anterior sulcus. Note low groove 

in bottom of delthyrial cavity which may have delimited pedicle adjustor area. USNM 160109A. 

2. Impression of exterior of pedicle valve. Note presence of fold in umbonal region, costae originating 

by both bifurcation and implantation. Concentric filae also prominent, together with concentric 

growth lines. Counterpart to sp·ecimen in figure 1. USNM 160109B. 

3. Impression of interior of brachial. valve. Note quadripartite form of muscle field, linear cardinal process laterally bounded by parallel ridges, and broad myophragm extending anteriorly from cardinal 

process to bisect muscle field. USNM 160110A. 

4. Impression of exterior of brachial valve. Note presence of prominent sulcus in umbonal region. Counterpart to s.pecimen in figure 3. USNM 160110B. 

5. Impression of interior of pedicle valve. Note the form of the muscle fi·dd and the pres.ence of a fold 

in the umbonal region which changes into a sulcus anteriorly. USNM 160111. 

6-12. Orthostrophia cf. 0. strophomenoides (Hall, 185·7) (p. 4). 

Beck Pond Limestone. USGS loc. 3499-SD, Spencer Lake quadrangle, Somerset County, Maine. X 1. 

6. Posterior view. Note relatively greater length of pedicle interarea and posteriorly sulcate brachial 

valve. USNM 125786B. 

7. Anterior view. Note uniplicate commissure with fold on brachial valve. USNM 125786B. 

8. Side view. Note somewhat greater convexity of pedicle valve. USNM 125786·B. 

9. View of p·edicle valve. Note sulcus present anteriorly and absent post·eriorly. USNM 125786B. 

10. View of brachial valve. Note sulcus present posteriorly and fold present anteriorly. USNM 125786B. 

11. Internal impression of pedicle valve. Note short dental lamellae, tripartite muscle field and impression of costellae anteromedially. USNM 125786A. 

12. Internal impression of brachial valve. Note quadripartite adductor impressions, short median septum, 

bladelike cardinal process, and stubby brachiophores. USNM 125785B. 

13-14. Schizoramma fissistriata Foerste, 1909 (p. 4). 

Interior and exterior of brachial valve ( X 2) . Note pair of ridges lateral to cardinal process ridge. 

USNM 87017. Osgood Formation. New Marion, Indiana 

15-17. Ortha;mbonites? sp. (p. 5). 

Latex replica of exterior: posterior, anterior, and brachial views. (X 3). USNM 125753. Kennebec Formation. USGS loc. 4317-CO, Brassua Lake quadrangle, Somerset County, Maine. 

18-26. Dolerorthis hobbstownensis Boucot, n. sp. (p.5·). 

Base of Hobbstown Formation. USGS loc. 3479-SD, Spence·r Lake quadrangle, Somerset County, Maine. 

Holotype, USNM 125796A, B. 

18, 22. Latex replica and imp·ression of interior of brachial valve (X 2). USNM 125796B. 

19. Posterior view of latex replica of exterior of pedicle valve (X 4). USNM 125903A. 

20, 25. Impres.s.ion and latex replica of exterior of brachial valve (X 2). USNM 125796A. 

21, 23. Impression and latex replica of exterior of pedicle valve (X 2). USNM 125903A. 

24, 26. Impression and latex replica of interior of pedicle valve (X 2). USNM 125797B. 
PROI'ESSJONAL PAPER 784 PLATE I 

3 

2 

4 

6 7 8 

12 

:t' . I ' 

·~ ) • f 

- • 1-'t 

20 21 17 

22 23 24 26 

ORTHOSTROPHIA , SCHIZORAMMA, ORTHAMBONITES?, AND DOLERORTHJS 
PLATE 2 

FIGURES 1-5. Dolerorthis cf D. hami (Amsden, 1951) (p. 7). 

1-4. Base of Hobbstown Formation. USGS loc. 3479-SD, Spencer Lake quadrangle, Somerset County, 

Maine. X 2. 

1, 2. Impressions of interior and exterior of pedicle valve. US'NM 125·79·5B, A. 

3, 4. Impressions of interior and exterior of brachial valve. USNM 125794A, B. 

5. Impression of interior of pedicle valve (X 3). USNM 160112. Harwood Mountain Formation. 

USGS loc. 5995-SD, Attean quadrangle, Somerset County, Maine. 

6--8. Dolerorthis? sp. (p. 7). 

Base of Hobbstown Formation .. USGS loc. 3479-SD, Spencer Lake quadrangle, Somerset County, Maine. 

X 2. 

6. Impression of interior of pedicle valve. USNM 125800B. 

7, 8. Latex replica and impression of exterior of pedicle valve. USNM 125800C. 

9-17. Ptychopleurella sp. (p. 7). 

Base of Hobbstown Formation. USGS loc. 3479-SD, Spencer Lake quadrangle, Somerset County, Maine. 

9, 11. Latex replica and impression of exterior of brachial valve (X 2). USNM 125801A. 

10. Latex replica of exterior of pedicle valve (posterior view X 3). USNM 125804. 

12, 13. Impression and latex replica of interior of pedicle valve (X 2). USNM 125802A. 

14, 16. Impression and latex replica of exterior of pedicle valve (X 2). USNM 125803B. 

15. Latex replica and impression of interior of brachial valve (X 2). USNM 125801B. 

18-22. l'alcourea sp. (p. 8) . 

Kennebec Formation. USGS loc. 4317-CO, Brassua Lake quadrangle, Somerset County, Maine. 

18. Latex replica of exterior (posterior view X 2). USNM 125751. 

19, 21. Impression of interior of brachial and pedicle valves (X 2). USNM 125752C. 

20, 22. Impression of exterior of pedicle and brachial valves (X 1). USNM 125750B, A. 

23-27. Resserella sp. (p. 9). 

Base of Hobbstown Formation. USGS loc. 3479-SD, Spencer Lake quadrangle, Somerset County, Maine. 

X 2. 

23. Impression of exterior of pedicle valve. USNM 125772A. 

24. Latex replica of exterior of pedicle valve. USNM 125774A. 

25. Impressions of interior of pedicle valve. USNM 125774B. 

26, 27. Impressions of exterior and interior of brachial valve. USNM 125773B, A. 

28-32. Isorthi8 sp.1 (p.10). 

Base of Hobbstown Formation. USGS 3479-SD, Spencer Lake quadrangle, Somerset County, Maine. 

X 2. 

28, 29. Impression and latex replica of interior of brachial valve. USNM 125828. 

30, 31. Impressions of interior and exterior of brachial valve. USNM 125829A, B. 

32. Impression of interior of pedicle valve. USNM 125827. 

33-35. Isorthis sp. 2 (p. 10). 

33. Impression of interior of brachial valve (X 3). USNM 125831A. Hardwood Mountain Formation. 

USGS loc. 3495-SD, Spencer Lake quadrangle, Somerset County, Maine. 

34, 35. Impressions of exterior and interior of pedicle valve (X 3). USNM 125826B, A. Parker Bog Formation. USGS loc. 3487-SD, Spencer Lake quadrangle, Somerset County, Maine. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 2 

29 30 32 

DOLERORTH!S, DOL ERORTHIS'?, PTYCHOPLEURELLA, VALCOUREA, RESSERELLA , AND JSORTHIS 
PLATE 3 

FIGURES 1-16. lsorthis sp. 3 (p. 10}. 

Hardwood Mountain Formation. Attean quadrangle, Somerset 

County, Maine. X 2. 

1. Impression of interior of pedicle valve. USNM 160113. 

USGS loc. 5587-SD. 

2. Impression of interior of brachial valve. USNM 160114. 

USGS loc. 5583-SD. 

3. Impression of interior of brachial valve. USNM 160115. 

USGS loc. 5586-SD. 

4. Impression of interior of pedicle valve. USNM 160116. 

USGS. loc. 5586-SD. 

5-8, 10. Impression of interior: anterior;liew, side view, pedicle 

view, brachial view, and posterior view (pedicle valve 

up}. USNM 160117. USGS loc. S583-SD. 

9. Impression of interior of pedicle valve. USNM 160118. 

USGS loc. 5583-SD. 

11-16. Impression of interior: brachial view, pedicle view, side 

view (pedicle valve to right}, side view (pedicle valve 

to left), posterior view (pedicle valve up), and anterior 

view (pedicle valve up). USNM 160119. USGS loc. 

5583-SD. 

17. lsorthis cf.l. perelegans (Hall, 1859) (p. 11). 

Impression of interior of brachial valve (X 2), USNM. 125813. 

Beck Bond Limestone. USGS loc. 3499-SD, Spencer Lake quadrangle, Somerset County, Maine. 

18-20. Levenea sp. (p. 11). 

Beck Pond Limestone. USGS loc. 3499-SD, Spencer Lake quadrangle, Somerset County, Maine. X 2. 

18, 19. Impression of interior of pedicle valve. USNM 125812, 

125811B. 

20. Impression of interior of brachial valve. USNM 125814. 

21. Unidentified orthoid (p. 11). 

Impression of interior of pedicle valve (X 4). USNM 126473. 

Lobster Mountain volcanics. USGS loc. 3280-SD, North East 

Carry quadrangle, Piscataquis County, Maine. 

22. Dicaelosia sp. (p. 11). 

Exterior of brachial valve (X 3). USNM 125810. Beck Pond 

Limestone. USGS loc. 3499-SD, Spencer Lake quadrangle, Somerset County, Maine. 

23-25. Discomyorthis musculosa solaris (Clarke, 1907) (p. 12). 

Tomhegan Formation. USGS loc. 2750-SD, Brassua Lake quadrangle, Somerset, County, Maine. X 20. 

23. Latex replica of exterior of brachial valve. USNM 125808A. 

24. Latex replica of interior of pedicle valve. USNM 125806. 

25. Impression of interior of pedicle valve. USNM 125806. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 3 

2 

5 6 

7 8 9 

11 

13 14 

16 

17 15 

19 

21 

18 

20 

25 22 

JSORTHIS , L E VENEA , UNIDENTIFIED ORTHOID, DICAELOSIA , AND DISCOMYORTHIS 
PLATE. 4 

FIGURES 1-3. Disc.omyorthis musculosa solaris (Clarke, 1007) (p. 12). 

Tomhegan Formation. USGS loc. 2750-SD, Brassua Lake quadrangle, Somerset County, Maine. X 2. 

1, 3. Latex replica and impression of interior of brachial valve. 

USNM 125809A. 

2. Impression of interior of pedicle valve. USNM 125807B. 

4, 5. Dalejina sp. 2 (p. 16). 

Impression of interior and exterior of brachial valve (X 3). 

USNM 125824B, A. Hardwood Mountain Formation. USGS loc. 

3469-SD, Spencer Lake quadrangle, Somerset County, Maine. 

6--9. Dalejina sp. 1 (p. 16). 

Base of Hobbstown Formation. USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somerset County, Maine. X 3. 

6, 8. Impression of exterior and interior of pedicle valve. USNM 

125821B, A. 

7, 9. Impression of interior and exterior of brachial valve. USNM 

125822B, A. 

10. Discomyorthis sp. (p. 13). 

Impression of interior of pedicle valve (X 3). USNM 125823. Beck 

Pond Limestone. USGS loc. 3499-SD, Spencer Lake quadrangle, 

Somerset County, Maine. 

11-18. Platyorthis planoconvexa (Hall, 1859) (p. 16). 

Lower sandstone of Tarratine Formation, Somerset. County, 

Maine. 

11, 12. Impression and latex replica of interior of pedicle valve 

(X 2) . USNM 125819. USGS loc. 3474-SD, Pierce Pond 

quadrangle. 

13, 15. Latex replica of interior and exterior of brachial valve (X 2, 

X 3). USNM 125820B, A. USGS loc. 2771-SD, Moosehead 

Lake quadrangle. 

14, 17. Impression and latex repli~a of exterior of pedicle valve 

(X 2). USNM 125825A. USGS loc. 3474-SD, Pierce Pond 

quadrangle. 

16, 18. Impressions of interior and exterior of brachial valve (X 

2). USNM 125820B, A. USGS loc. 2771-SD, Moosehead 

Lake quadrangle. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 4 

4 5 

1 

2 

6 7 

3 

9 

10 12 

11 

15 

14 

13 

16 17 18 

DJSCOMYORTHIS, DALEJ!NA, AND PLATYORTHJS 
PLATE 5 

FIGURES 1-11. Salopina hitchcocki Walmsley, Boucot, and Harper, 1969 (p. 18). 

1, 2. Latex replica and impression of interior of brachial valve 

( X 3). Lower sandstone of Tarratine Formation. USGS 

loc. 2872-SD, Pierce Pond quadrangle, Somerset County, 

Maine. USNM 125783A. 

3, 4. Latex replica and impression of exterior of brachial valve 

(X 3). Lower sandstone of Tarratine Formation. USGS 

loc. 2872-SD, Pierce Pond quadrangle, Somerset County, 

Maine. USNM 125783B. 

5. Latex replica of interior of pedicle valve ( X 3) . Lower 

sandstone of Tarratine Formation. USGS loc. 2743- SD, 

Moosehead Lake quadrangle, Somerset County, Maine. 

USNM 125798A. 

6. Impression of interior of pedicle valve ( X 3). Seboomook 

Formation. USGS loc. 2884-SD, Chesuncook quadrangle, 

Piscataquis County, Maine. USNM 125793A. 

7, 8. Latex replica and impression of interior of brachial valve 

(X 3). Tarratine Formation. USGS loc. 2861-SD, North 

East Garry quadrangle, Somerset County, Maine. Holotype, USNM 125782B. 

9. Impression of interior of pedicle valve (X 3) . Lower sandstone of Tarratine Formation. USGS loc. 2705-SD, Brassua Lake quadrangle, Somerset County, Maine. USNM 

125781B. 

10, 11. Impression and latex replica of exterior of brachial valve 

(X 3). Tarratine Formation. USGS loc. 2861-SD, North 

East Carry quadrangle, Somerset County, Maine. Holotype, USNM 125782A. 

12- 14. Gypidula sp. 1 (p. 19). 

Hardwood Mountain Formation, USGS loc. 3488-SD, Spencer 

Lake quadrangle, Somerset County, Maine. 

12. View of inner crural plates and hinge plate (X 3). USNM 

126508. 

13, 14. Side view of spondylium (X 3) and exterior of pedicle 

valve (X 2). USNM 126509A. 

15-23. Gypidula sp. 2 (p. 19). 

15- 19. Exterior : side, brachial, pedicle, posterior, and anterior 

views (X 1) . Hardwood Mountain Formation. USGS loc. 

2728-SD, Spencer Lake quadrangle, Somerset County, 

Maine. USNM 125840. 

20-23. Anterior (brachial valve above), opposite side, and posterior views ( X 2). Hardwood Mountain Formation. 

USGS loc. 5587-SD, Attean quadrangle, Somerset County, 

Maine. USNM 160120. 
GEOLOGICAL SURVEY PROPESSIONAL PAPER 784 PLATE 5 

2 

SALOPJNA AND GYPIDULA 
PLATE 6 

FIGURES 1, 2. Gypidula sp. 2? (p. 19). 

Views of silicified cardinalia (X 1). USNM 125842. Hardwood 

Mountain Formation. USGC loc. 3485--SD, Spencer Lake quadrangle, Somerset County, Maine. 

3-8. Sieberella beckensis Boucot, n. sp. (p. 20). 

Beck Pond Limestone. USGS loc. 3499~SD, Spencer Lake quadrangle, Somerset County, Maine. 

3, 6, 8. Exterior (X 1), side (X 2), and posterior (X 2) views of 

pedicle valve. Holotype, USNM 125841A. 

4. Exterior of brachial valve (X 1). USNM 125838B. 

5. Side view of spondylium (X 3). USNM 125837. 

7. Cross section of brachial valve (X 3). Note lyre-shaped 

cross section of brachial lamellae. USNM 125839. 

9, 10. Pentamerus? sp. (p. 20). 

Lime-silicate hornfels of Early Silurian age. USGS loc. 3475-SD, 

Limestone Hill, Stratton quadrangle, Somerset County, Maine. 

9. Impression of interior of pedicle valve (X 2). USNM 125835. 

10. Partly exfoliated pedicle valve (X 1). USNM 125836B. 

11. Sowerbyites? sp. (p. 20). 

Latex replica of exterior of brachial valve (X 3). USNM 

126152A. Kennebec Formation. USGS loc. 4317-CO, Brassua 

Lake quadrangle, Somerset County, Maine. 

12-16. Leptaena "rhomboidalis" (Wilckens, 1769) (p. 20). 

Spencer Lake quadrangle, Somerset County, Maine. 

12. Exterior of pedicle valve (X 2). USNM 126141B. Beck 

Pond Limestone. USGS loc. 3499-SD. 

13, 15. Impression (X 1) and latex replica (X 2) of interior of 

brachial valve. USNM 126146A. Beck Pond Limestone. 

USGS loc. 3497-SD. 

14, 16. Impressions of interior and exterior of pedicle valve (X 

1). USNM 126127B, A. Base of Hobbs town Formation. 

USGS loc. 3479-SD. 

17-19. Stropheodonta cf. S. demissa (Conrad, 1842) (p. 21). 

Tomhegan Formation. Brassua Lake quadrangle, Somerset 

County, Maine. 

17. Latex replica of exterior of brachial valve (X 3). USNM 

126145B. USGS loc. 2750-SD. 

18, 19. Latex replica of exterior and impression of interior of 

brachial valve (X 2). USNM 126144A. USGS loc. 

2820-SD. 

20-23. aff. Stropheodonta sp. (p. 21). 

Tomhegan Formation. Brassua Lake quadrangle, Somerset 

County, Maine. 

10. Latex replica of exterior of ped·icle valve (X 2). USNM 

126153A. USGS loc. 2820-SD. 

21. Impression of interior of pedicle valve (X 1). USNM 126126A. 

USGS loc. 2750-SD. 

22. Latex replica of interior of pedicle valve (X 3). USNM 

126125. USGS loc. 2820-SD. 

23. Latex replica of exterior of brachial valve (posterior view 

X 3). USNM 126126B. USGS loc. 2820-SD. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 6 

3 

4 5 

10 

12 

17 

19 

GYPIDULA , S!EBERELLA, PENTAMERUS?, SOWERBYITES? LEPTAENA, AND STROPHEODONTA 
PLATE 7 

FIGURES 1-9. Leptostrophia cf. L. magnifica (Hall, 1857) (p. 21). 

Lower sandstone of Tarratine Formation. Somerset County, Maine. 

1, 3. Impression and latex replicas of interior of pedicle valve (X 

1). USNM 126121. USGS loc. 2813-SD, Pierce Pond quadrangle. 

4, 8. Latex replica and impression of interior of brachial valve 

(X 4). USNM 126158B. USGS loc. 2813-SD, Pierce Pond 

quadrangle. 

5. Latex replica of exterior (posterior brachial view X 1). 

USNM 126159. USGS loc. 2705-SD, Brassua Lake quadrangle. 

6. Latex replica of interior of brachial valve (X 2). USNM 

126142. USGS loc. 2813-SD, Pierce Pond quadrangle. 

7. Impression of interior of pedicle valve (X 1). USNM 126122. 

USGS loc. 2813-SD, Pierce Pond quadrangle. 

9. Impression of interior of pedicle valves (X 1). USNM 126123. 

USGS loc. 2705-SD, Brassua Lake quadrangle. 

10, 11. Leptostrophia? sp. (p. 22). 

Parker Bog Formation. USGS loc. 3477-SD, Pierce Pond quadrangle, Somerset County, Maine. 

10. Impression of interior of brachial valve (X 3). USNM 126120. 

11. Impression of interior of pedicle valve (X 2). USNM 126147B. 

12, 13. Leptostrophia sp. or Protoleptostrophia sp. (p. 22). 

Latex replica and impression of interior of pedicle valve (X 1). 

USNM 126118A. Seboomook Formation. USGS loc. 2857-SD, 

Brassua Lake quadrangle, Somerset County, Maine. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 7 

3 

10 

5 

6 11 

7 

9 

LEPTOSTROPH!A, LEPTOSTROPHIA ?, AND PROTOLEPTOSTROPHIA 
PLATE 8 

FIGURES 1-8. Protoleptostrophia cf. P. blainvillei (Billings, 1874) (p. 22). 

Tomhegan Formation. Brassua Lake quadrangle, Somerset County, 

Maine. 

1. Latex replica of exterior of pedicle valve (X 2). USNM 

126154A. USGS loc. 2820-SD. 

2, 3. Latex replica and impression of interior of brachial valve 

(X 2). USNM 126140. USGS loc. 2750-SD. 

4. Impression of exterior of brachial valve (X 1). U SNM 

126137B. USGS loc. 2820-SD. 

5, 6. Impression and latex replica of interior of brachial valve 

(X 1). USNM 126137A. USGS 2820-SD. 

7, 8. Latex replica of exterior and impression of interior of pedicle valve (X 1). USNM 126136B, A. USGS loc. 2820-SD. 

9-13. Protoleptostrophia sp. (p. 23). 

Lower sandstone of Tarratine Formation. Somerset County, 

Maine. (X 2). 

9, 10. Impression of interior and latex replica of exterior of 

pedicle valve. USNM 126135B, A. USGS loc. 2719-SD, 

Long Pond quadrangle. 

11. Impression of interior of brachial valve. USNM 126134A. 

USGS loc. 2719-SD, Long Pond quadrangle. 

12, 13. Latex replicas of interior of brachial valve. USNM 126133, 

126132. USGS loc. 2701-SD, Brassua Lake quadrangle. 

14-18. Strophonella cf. S. punctulifera (Conrad, 1838) (p. 23). 

Parker Bog Formation. USGS loc. 3477-SD, Pierce Pond quadrangle, Somerset County, Maine. X 1. 

14. Latex replica of exterior of pedicle valve from slab. USNM 

126119. 

15. Latex replica of exterior of pedicle valve from slab. USNM 

126119. 

16, 17. Latex replica and impression of interior of pedicle valve. 

USNM 126143. 

18. Latex replica of interior of brachial valve, USNM 126157A. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 8 

2 

1 3 

6 

4 

11 

7 

9 

12 

8 

10 

13 

15 

14 16 17 

PROTOLEPTOSTROPHIA AND STROPHONELLA 
PLATE 9 

FIGURES 1- 11. "Schuchertella" becraftensis (Clarke, 1900) (p. 24). 

1- 6. Lower sandstone of Tarratine Formation. Long Pond quadrangle, Somerset County, Maine. 

1, 3. Impression and latex replica of interior of brachial valve (X 3). USNM 126138. USGS 

loc. 2719-SD. 

2, 4. Impression and latex replica of brachial valve (X 3). USNM 126151B, A. USGS loc. 

2777- SD. 

5. Latex replica of interior of brachial valve (X 2). USNM 126160B. USGS loc. 2719-SD. 

6. Latex replica of exterior of pedicle valve (posterior view X 4). USNM 126162A. USGS 

loc. 2719-SD. 

7. Impression of exterior of brachial valve (X 1). USGS 126139B. Seboomook Formation. USGS 

loc. 2761- SD, Brassua Lake quadrangle, Somerset County, Maine. 

8, 11. Impression and latex replica of interior of pedicle valve (X 1). USNM 126156B. Seboomook 

Formation. USGS 3091-SD, Long Pond quadrangle, Somerset County, Maine. 

9, 10. Impression and latex replica of interior of pedicle valve (X 3). USNM 126124. Lower sandstone 

of Tarratine Formation. USGS loc. 2720-SD, Long Pond quadrangle, Somerset County, Maine. 

12- 14. "Schuchertella" sp. · ( p. 24). 

Tomhegan Formation. USGS loc. 2820-SD, Brassua Lake quadrangle, Somerset County, Maine. 

12. Latex replica of interior of brachial valve (posterior view X 2). USNM 126148A. 

13, 14. Latex replicas of interior and exterior of brachial valve (X 1). USNM 126148A, B. 

15-17. Hipparionyx sp. (p. 24). 

McKenney Ponds member of Tarratine Formation. USGS loc. 2810-SD, Pierce Pond quadrangle, Somerset County, Maine. X 1. 

15. Impression of interior of pedicle valve. USNM 126149A. 

16. Interior of pedicle valve. USNM 126149B. 

17. Impression of interior of brachial valve. USNM 126150C. 

18-20. Leptaenisca sp. (p. 25). 

Beck Pond Limestone. USGS loc. 3499-SD, Spencer Lake quadrangle, Somerset County, Maine. X 2. 

18. Exterior of pedicle valve (posterior view). USNM 126129. 

19, 20. Partly exfoliated pedicle valves. USNM 126129, 126128B. 

21-37. Cyrtoniscus nectus (Clarke, 1907) (p. 25). 

Tomhegan Formation. USGS Joe. 2852-SD, Brassua Lake quadrangle, Somerset County, Maine. 

21. Latex replica of interior of pedicle valve (X 3). Specimen misplaced. 

22. Impression of inte·rior of pedicle valve (X 4). USNM 127392B. 

23, 24. Latex replicas of exterior and intr of brachial valve (X 4). USNM 126223B, A. 

25, 26. Impression of interior and latex replica of exterior of pedicle valve (X 4) . USNM 126229. 

27, 35. Impressions of exterior and interior of brachial valve (X 4). USNM 126223B, A. 

28. Impression of exterior of brachial valve (X 3). USNM 126248. 

29, 30. Impressions of interior and exterior of brachial valve (X 4). USNM 126228. 

31. Latex replica of interior of pedicle valve (X 3). USNM 126247. 

32-34. Latex replicas of interior of brachial valve (X 4). USNM 126227, 126222, 126223A. 

36. Latex replica of exterior of pedicle valve (X 4). USNM 126231A. 

37. Impression of interior of pedicle valve (X 4). USNM 127391A. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 9 

34 35 36 37 

"SCHUCHERTELLA ", HIPPARIONYX, LEPTAENISCA, AND CYRTONISCUS 
PLATE 10 

FIGURES 1-7. Eccentricosta sp. (p. 25). 

Hardwood Mountain Formation. Attean quadrangle, Somerset 

County, Maine. 

1. Impression of exterior of brachial valve (X 2). USNM 160121. 

USGS loc. 5583-SD. 

2. Impression of exterior of pedicle valve (X 3). Note impression 

of spines and undulating costellae. USNM 160122A. USGS 

loc. 5995-SD. 

3. Impression of interior of pedicle valve (X 3). Note the short 

myophragm at the posterior of the valve. USNM 160122B. 

USGS loc. 5995-SD. 

4. Impression of exterior of ped.icle valve (X 2). Note impression 

of spines and undulating costellae. USNM 160123. USGS loc. 

4841-SD. 

5. Impression of exterior of pedicle valve (X 2). Note undulating 

costellae. USNM 160124. USGS loc. 5583-SD. 

6. Impression of interior of pedicle valve (X 3). USNM 160125. 

USGS loc. 4841-SD. 

7. Impression of exterior of pedicle valve (X 2). Note impressions 

of spine bases and undulating costellae. USNM 160126. USGS 

loc. 4841-SD. 

8-12. Dawsonelloides canadensis (Billings, 187 4) ( p 26). 

Lower sandstone of Tarratine Formation, Somerset County, Maine. 

8. Impression of interior of pedicle valve (X 1). USNM 126244. 

USGS loc. 2813-SD, Pierce Pond quadrangle. 

9. Impression of interior of brachial valve (X 2). USNM 126246. 

USGS loc. 2813-SD, Pierce Pond quadrangle. 

10. Impression of interior of pedicle valve (X 1). USNM 126233. 

USGS loc. 2701-SD, Brassua Lake quadrangle. 

11. Impression of interior of pedicle valve (X 1). USNM 126251B. 

USGS loc. 2701-SD, Brassua Lake quadrangle. 

12. Latex replica of exterior of brachial valve (posterior view X 

2). USNM 126252. USGS loc. 2701-SD, Brassua Lake quadran.gle. 
GEOLOGICAL SURVEY PROfESSIONAL PAPER 784 PLATE 10 

2 

4 

3 5 

7 8 

6 

10 

11 12 

ECCENTRICOSTA AND DA WSONELLOIDES 
PLATE 11 

FIGURE 1-7. Dawsonelloides canadensis (Billings, 1874) (p. 26). 

Lower sandstone of Tarratine Formation. Somerset County, Maine. 

1, 2. Latex replicas of interior of pedicle and brachial valves ( X 1). 

USNM 126250, 126245. USGS loc. 2701-SD, Brassua Lake 

quadrangle. 

3, 4. Latex replicas of interior of pedicle valve (X 1, X 4). USNM 

126233, 126253B. USGS loc. 2813-SD, Brassua Lake quadrangle. 

5. Latex replica of interior of brachial valve (X 1). USNM 

126239A, USGS loc 2701-SD, Brassua Lake quadrangle. 

6. Latex replica of exterior of pedicle valve (X 1). USNM 

126253C. USGS loc. 2813-SD, Pierce Pond quadrangle. 

7. Impression of interior of pedicle valve ( X 1). USNM 126250. 

USGS loc. 2701- SD, Brassua Lake quadrangle. 

8-16. Eodevonaria arcuata (Hall, 1857) (p. 27). 

Tomhegan Formation. USGS loc. 2820-SD, Brassua Lake quadrangle, Somerset County, Maine. 

8, 9. Impressions of interior of pedicle valve (X 2). USNM 

126235A, 126230A. 

10. Latex replica of exterior of pedicle valve ( X 2) . USNM 

126230B. 

11, 14. Latex replica and impression of interior of brachial valve 

(X 2). USNM 126238A. 

12, 16. Impression and latex replica of exterior of brachial valve 

( X 2, X 4). USNM 126234B, A. 

13. Impression of interior of pedicle valve (X 2). USNM 

126232A. 

15. Impression of exterior of brachial valve (X 2) . USNM 

126226A. 

17-25. Chonostrophiella complanata (Hall, 1857) (p. 28). 

Lower sandstone of Tarratine Formation. USGS loc. 2718-SD, 

Long Pond quadrangle, Somerset County, Maine. 

17, 23. Impression and latex replica of interior of brachial valve (X 

2). USNM 126236A. 

21, 

18. Impression of interior of pedicle valve (X 2). USNM 

126254B. 

19. Impression of interior of brachial valve (X 2) . USNM 

126241. 

20. Impression of interior of brachial valve (X 1). USNM 

126237C. 

22. Impression and latex replica of interior of pedicle valve (X 

1). USNM 126225. 

24, 25. Latex replicas of interior and exterior of pedicle valve (X 

2). USNM 126240, 126243. 
GEOLOGICAL SURVEY 

1 

5 

9 

14 

18 

21 

2 

6 

10 

15 

7 

~~~ '· . 

~.·.·.'.:.··~ ,(~"''"-:' .... ·'' !. -, ·~ ' ' ' 

. \·'<'~ ~ ,\ ~~.<: \ ' '.' 

11 

22 

24 

PROFESSIONAL PAPER 784 PLATE ll 

3 

4 

8 

12 13 

17 

16 

19 20 

23 

25 

DA WSONELLOIDES, EODEVONAR/A, AND CHONOSTROPHIELLA 
PLATE 12 

FIGURES 1, 2. Chonostrophiella complanata (Hall, 1857) (p. 28). 

Latex replica of interior (X 2) and exterior (X 1) of pedicle 

valve. USNM 126242A, B. Lower sandstone of Tarratine Formation. USGS loc. 2718-SD, Long Pond quadrangle, Somerset 

County, Maine. 

3-11. Cupularostrum macrocosta Boucot, n. sp. (p. 29). 

Tomhegan Formation, Brassua Lake quadrangle, Somerset County, 

Maine. 

3. Latex replica of exterior of pedicle valve (X 1). USNM 

125856. USGS loc. 2750-SD. 

4. Impression of the interior of pedicle valve (X 1). USNM 

125857. USGS loc. 2842-SD. 

5. Impression of interior of brachial valve (posterior view 

X 3). USNM 125855A. USGS loc. 2750-SD. 

6, 7. Impressions of interior of brachial valve (X 3, X 1). USNM 

125904B. USGS loc. 2750-SD. 

8, 10. Impression (posterior view X 3) and latex replica (X 2) 

of exterior of brachial valve. USNM 125852. USGS loc. 

2842-SD. 

9. Impression of interior of pedicle valve (X 1). Holotype, 

USNM 125851A. USGS loc. 2750-SD. 

11. Latex replica of interior of pedicle valve (X 1). USNM 

125852A. USGS loc. 2842-SD. 

12-21. Cupularostrum? sp. (p. 30). 

Beck Pond Limestone. USGS loc. 3601-SD, Spencer Lake quadrangle, Somerset County, Maine. X 3. 

12, 13, 16, 19, 21. Exterior: brachial valve, pedicle valve, posterior, side, and anterior views. USNM 

125859. 

14, 15, 17, 18, 20. Exterior: side, anterior, pedicle valve, brachial 

valve, and anterior views. USNM 125862. 

22-26. A ncillotoechia sp. ( p. 30). 

Exterior: side, posterior, anterior, and brachial valve views (X 

3); pedicle valve (X 4). USNM 125902. Beck Pond Limestone. 

USGS loc. 3499-SD, Spencer Lake quadrangle, Somerset 

County, Maine. 

27-31. "Ancillotoechia" cf. A. altisulcata (Amsden, 1951) (p. 31). 

Exterior: posterior, anterior, side, brachial valve, and pedicle 

valve views (X 2). USNM 125854. Hardwood Mountain Formation. USGS loc. 3488-SD, Spencer Lake quadrangle, Somerset, 

County, Maine. 

32-36. Sphaerirhynchia sp. 1 (p. 31). 

Exterior: side, pedicle valve, brachial valve, posterior, and anterior views (X 2). USNM 125874. Hardwood Mountain Formation. USGS loc. 3470-SD, Spencer Lake quadrangle, Somerset, County, Maine. 
GEOLOGICAL SURVEY 

2 

1 

7 

6 

12 13 

10 

15 

17 

18 19 

22 

21 

28 

24 

23 

8 

16 

. 20 

PROFESSIONAL PAPER 784 PLATE 1'2 

3 

5 

14 

29 

4 

~ 

,v_;f.; . ,. 

>:W/};,Ilw' 

~!':.t.O-·,~" 

9 

11 

32 33 

34 

CHONOSTROPHIELLA, CUPULAROSTRUM, CUPULAROSTRUM?, ANCILLOTOECHIA, "ANCILLOTOECHIA ", 

AND SPHAERIRHYNCHIA 
PLATE 13 

FIGURES 1-6. Sphaerirhynchia sp. 2 (p. 32'). 

Beck Pond Limestone. USGS loc. 3499-SD, Spencer Lake quadrangle, Somerset County, Maine. 

1, 3-6. Exterior: pedicle valve, posterior, brachial valve, anterior, 

and side views (X 3). USNM 125876. 

2. Impression of interior of brachial valve (X 1). USNM 

125877. 

7-12. Sphaerirhynchia sp. 3 (p. 33). 

Beck Pond Limestone. USGS loc. 3601-SD, Spencer Lake quadrangle, Somerset County, Maine. X 1. 

7. Impression of interior of pedicle valve. USNM 125871. 

8-12. Exterior: brachial valve, pedicle valve, posterior, anterior, 

and side views. USNM 125870. 

13-18. Sphaerirhynchia? sp. (p. 33). 

Hardwood Mountain Formation. USGS loc. 3488-SD, Spencer Lake 

quadrangle, Somerset, County, Maine. 

13-15. Impression of interior of pedicle valve, brachial valve, and 

posterior view (X 2). USNM 127385A. 

16, 17. Exterior: side and anterior views (X 2). USNM 127385A. 

18. Section of brachial and pedicle valves (X 5). USNM 

127385B. 

19-25. Sulcatina sp. (p. 33). 

Hardwood Mountain Formation. USGS loc. 3488-SD, Spencer Lake 

quadrangle, Somerset County, Maine. X 1. 

19. Latex replica of exterior (posterior view). USNM 125853A. 

20, 25. Partly exfoliated exterior (side and posterior views). 

USNM 125847B. 

21. Exterior of brachial valve. USNM 125848. 

22. Impression of interior (anterior view). USNM 125847A. 

23, 24. Impression of interior of pedicle and brachial valves. USNM 

125850. 

2~28. Sphaerirhynchia sp. 1 ( p. 31). 

Hardwood Mountain Formation. USGS loc. 558~SD, Attean quadrangle, Somerset County, Maine. X 2. 

26, 27. Impressions of interior (posterior view). USNM 160127, 

160128. 

28. Impression of interior of pedicle valve. Note raised impressions for adductor atttachment surrounded by diductor 

field. USNM 160129. 
GEOLOGICAL SURVEY PROFESS IONAL PAPER 784 PLATE 13 

1 2 3 

4 

5 

~,· 

-~ I r • 

1.

·( ~' . 

. '- t ~ •. • ( 

.:· ,; 

10 

7 8 9 

13 14 15 16 

18 

19 

20 17 

22 

28 

23 

26 27 

SPHA ERIRHYNCHJA , SPHAERIRHYNCH/A ?, AND SULCATINA 
PLATE 14 

FIGURES 1-5. Costellirostra sp. (p. 34). 

Exterior: brachial valve, pedicle valve, posterior, anterior, and 

side views (X 3). USNM 125885. McKenney Ponds Member of 

Tarratine Formation. USGS loc. 2806--SD, Pierce Pond quadrangle, Somerset County, Maine. 

6--13. Eatonia cf E. medialis (Vanuxem, 1842) (p. 34). 

Beck Pond Limestone. USGS loc. 3499-SD, Spencer Lake quadrangle, Somerset County, Maine. 

6, 8-11. Exterior: side (X 2), brachial valve (X 1), anterior (X 

2), posterior (X 2), and pedicle valve ( X 2) views. 

USNM 125882B. 

7, 12. Impressions of interior of pedicle (X 1) and brachial (X 

3) valves. USNM 125873. 

13. Impression of interior of brachial valve (X 1). USNM 

125872. 

14-21. Machaeraria mainensis Boucot, n. sp. (p. 35). 

Base of Hobbstown Formation. USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

14, 15. Impression and latex replica of interior of pedicle valve 

(X 2). USNM 125867A. 

16. Latex replica of exterior of pedicle valve (X 2). USNM 

125867A. 

17, 19. Impression (X 3) and latex replica (X 4) of interior of 

brachial valve. Holotype, USNM 125869A. 

18. Latex replica of interior (posterior view X 4). Holotype, 

USNM 125869A. 

20. Latex replica of exterior of pedicle valve (X 3). USNM 

125868. 

21. Latex replica of exterior (posterior view X 3). USNM 

125868. 

22-27. Atrypa cf. A. tennesseensis Amsden, 1949 (p. 36). 

Base of Hobbstown Formation. USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somerset, County, Maine. 

22, 23. Impressions of exterior of pedicle and brachial valves (X 

2). USNM 126003A, B. 

24. Impression of interior of brachial valve (X 2). USNM 

126003C. 

25, 27. Latex replica and impression of interior of pedicle valve 

(X 3). USNM 126002. 

26. Latex replica of exterior of pedicle valve (X 3) . U SNM 

126004. 

28, 29. Atrypa cf. A. arctostriata Foerste, 1903 (p. 36). 

Impressions of exterior and interior of brachial valve (X 3). 

USNM 126014A, 126015B. Base of Hobbstown Formation. USGS 

loc. 3479-SD, Spencer Lake quadrangle, Somerset County, 

Maine. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 14 

1 

11 

13 14 

15 

16 

17 18 19 

22 23 24 

20 

25 26 27 28 29 

COSTELLIROSTRA, EATON/A, MACHAERARIA, AND ATRYPA 
PLATE 15 

FIGURES 1-6. Atrypa "reticularis" (Linnaeus, 1767) (p. 36). 

1-3. Tomhegan Formation. USGS loc. 2750-SD, Brassua Lake quadrangle, Somerset County, Maine. 

X 1. 

1, 3. Impression and latex replica of interior of pedicle valve. USNM 126011. 

2. Latex replica of exterior of pedicle valve. USNM 126010A. 

4. Exterior of brachial valve (X 1). USNM 126008A. Hardwood Mountain Formation. USGS loc. 

3488-SD, Spencer Lake quadrangle, Somerset County, Maine. 

5, 6. Latex replica and impression of interior of brachial valve (X 1). USNM 126068B. Tomhegan Formation. USGS loc. 2820-SD, Brassua Lake quadrangle, Somerset County, Maine. 

7-15. Lissatrypa sp. (p. 37). 

7-13. Hardwood Mountain Formation. Spencer Lake quadrangle, Somerset County, Maine. 

7, 8. Latex replicas of interior of pedicle (X 2) and brachial (X 3) valves. USNM 125908B, 

A. USGS loc. 3473-SD. 

9. Partly exposed spire (X3). USNM 126000. USGS loc. 3488-SD. 

10, 11. Impression and latex replica of interior of brachial valve (X 3). USNM 125905B, A. 

USGS loc. 3473-SD. 

12. Impression of interior of pedicle valve (X 2) . USNM 125908B. USGS loc. 3473-SD. 

13. Impression of interior of brachial valve (X 3). USNM 125905A. USGS loc. 3473-SD. 

14, 15. Impressions of interior and exterior of pedicle valve (X 3). Note the trapezoidal impression of 

the muscle field (fig. 14) and faint, concentric growth lines (fig. 15). USNM 160130A, B. Hardwood Mountain Formation. USGS loc. 4843-SD, Attean quadrangle, Somerset County, Maine. 

16. Nanospira? sp. (p. 37). 

Partly exfoliated exterior of brachial valve (X 5) . USNM 126108A. Base of Hobbstown Formation. 

USGS loc. 3479-SD, Spencer Lake quadrangle, Somerset County, Maine. 

17-24. Leptocoelia flabellites (Conrad, 1841) (p. 38). 

17-19, 22- 24. Lower sandstone of Tarratine Formation. USGS loc. 2718- SD, Long Pond quadrangle, 

Somerset County, Maine. 

17. Impression of interior of brachial valve (X 2). USNM 126005B. 

18, 22. Impression and latex replica of interior of pedicle valve (X 2). USNM 126001. 

19. Impression of exterior of pedicle valve (X 2). USNM 126005A. 

23. Latex replica of interior of brachial valve (X 2). USNM 127387. 

24. Latex replica of exterior of brachial valve (X 3) . USNM 126012. 

20. Exterior of brachial valve (X 2). USNM 126009. Seboomook Formation. USGS loc. 3094-SD, 

Long Pond quadrangle, Somerset County, Maine. 

21. Exterior of brachial valve (X 2). USNM 125907. Seboomook Formation. USGS loc. 2880-SD, 

Attean quadrangle, Somerset County, Maine. 

25-32. Coelospira sp. (p. 38). 

25-28. Hardwood Mountain Formation. USGS loc. 3488-SD, Spencer Lake quadrangle, Somerset County, 

Maine. X 4. 

25, 26. Impressions of interior of pedicle and brachial valves. US~M 126007C. 

27. Latex replica of exterior of brachial valve. USNM 126007 A. 

28. Latex replica of exterior of brachial valve. USNM 126007AA. 

29- 32. Hardwood Mountain Formation. USGS loc. 5995-SD, Attean quadrangle, Somerset County, Maine. 

X 3. 

29. Impression of interior of pedicle valve. USNM 160131. 

30. Impression of interior of pedicle valve (turned to side) USNM 160132A. 

31, 32. Impressions of exterior and interior of pedicle valve. USNM 160132B. 160133. 

33-35. Hedeina cf. H. macropleura (Conrad, 1840) (p. 39). 

33. Partly exfoliated exterior of brachial valve (X 1). USNM 126076A. Beck Pond Limestone. USGS 

loc. 3499-SD, Spencer Lake quadrangle, Somerset County, Maine. 

34. Exterior of pedicle valve (X 1). U SNM 126006. McKenney Ponds Member of Tarratine Formation. USGS loc. 2806-SD, Pierce Pond quadrangle, Somerset County, Maine. 

35. Impression of interior of brachial valve (posterior view X 2). USNM 126076A. Beck Pond Limestone. USGS loc. 3499-SD, Spencer Lake quadrangle, Somerset County, Maine. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 15 

33 34 35 

ATRYPA, LISSATRYPA, NANOSPIRA? , LEPTOCOELlA, COELOSPIRA, AND HEDEINA 
PLATE 16 

FIGtJRES 1-5. Delthyris cf. D. kozlowskii Amsden, 1951 (p. 39). 

Base of Hobbstown Formation. USGS loc. 3479-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

1. Impression of interior of pedicle valve ( X 2) . U SNM 126038. 

2. Impression of interior of brachial valve ( X 3. USNM 126027 A. 

3. Latex r eplica of exterior of pedicle valve ( X 2) . USNM 126036B. 

4. Impression of exterior of P!.ldicle valve (X 6). USNM 126036B. 

5. Impression of interior of pedicle valve (X 2). U SNM 126025B. 

6, 7. Howellella? sp. (p. 39). 

6. Cross section ( X 3), showing presence of short dental lamellae 

and absence of a median septum. USNM 160134. Hardwood 

Mountain Formation. USGS loc. 4841-SD, Attean quadrangle, 

Somerset County, Maine. 

7. Impression of interior of pedicle valve (X 3). USNM 126020. 

Hardwood Mountain Formation. USGS loc. 2950- SD, Spencer 

Lake quadrangle, Somerset County, Maine. 

8, 9. Howellella? cf. H. cyclopterus (Hall, 1857) (p. 40). 

Latex replica and impression of exterior of pedicle valve ( X 1) . 

USNM 126257A. Beck Pond Limestone. USGS loc. 3499- SD, 

Spencer Lake quadrangle, Somerset County, Maine. 

10-18. "Howellella" tomheganensis Boucot, n. sp. (p. 40). 

Tomhegan Formation. USGS loc. 2750-SD, Brassua Lake quadrangle, Somerset County, Maine. 

10. Latex replica of interior of pedicle valve (X 1). USNM 

126017B. 

11. Latex replica of interior of brachial valve (X 2). USNM 

126032B. 

12. Latex replica of exterior of brachial valve (X 1). Holotype, 

USNM 126016B. 

13. Impression of interior of brachial valve, posterior view (X 

2). Holotype, USNM 126016A. 

14. Impression of interior of brachial valve (X 1). Holotype, 

USNM 126016A. 

15. Latex replica of exterior of pedicle valve (X 2). USNM 

126026A. 

16. Impression of interior of pedicle valve (X 3). USNM 

125026A. 

17, 18. Latex replica and impression of interior of pedicle valve 

(X 2). USNM 126045B, A. 

19- 25. Acrospirifer murchisoni (Castelnau, 1843) (p. 41). 

Lower sandstone of Tarratine Formation. USGS loc. 2718-SD, 

Long Pond quadrangle, Somerset County, Maine. X 1. 

19. Latex replica of exterior of pedicle valve. USNM 126047A. 

20, 23. Latex replica and impression of interior of pedicle valve. 

USNM 126047D. 

21, 24. Latex replica and impression of interior of brachial valve. 

USNM 126043. 

22. Latex replica of exterior of brachial valve. USNM 127386B. 

25. Impression of interior of pedicle valve. USNM 126042A. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 16 

2 

~ 'ftf·· .. •• ~tt • . ·. I 

~ ,> ·~ .-e., f ..,.. . .~ 

3 

1 

~,..... 

,.~ J L' .~ 

I '\ : . . 

6 4 

8 

... ~· . .... ,' 

( " 

'.!'' \~· \ 

9 

7 

5 

13 

12 

10 11 

~ .-4: 

I 

~lj;li .-" 

I .( 16 

14 

15 

19 

17 

18 

20 

21 

. J}' 

·. IJ ' 

22 23 24 25 

DELTHYRIS, HOWELLELLA ?, "HOWELLELLA ", AND ACROSPIRIFER 
PLATE 17 

FIGURES 1-9. Acrospirifer atlanticus (Clarke, 1907) (p. 46). 

Tomhegan Formation. Brassua Lake quadrangle, Somerset 

County, Maine. 

1, 2. Impression and latex replica of interior of brachial valve 

(X 1). USNM 126041B. USGS loc. 2750-SD. 

3. Latex replica of exterior of brachial valve (X 1). USNM 

126041A. USGS loc. 2750-SD. 

4, 9. Latex replica of exterior of brachial valve (X 1, X 4). 

USNM 126163B. USGS loc. 2750-SD. 

5, 6. Impression and latex replica of interior of pedicle valve 

(X 1). USNM 126019B. USGS loc. 2820-SD. 

7. Latex replica of interior of pedicle valve (X 1). USNM 

127388B. USGS loc. 2750-SD. 

8. Impression of interior of pedicle valve (X 1). USNM 

126031B. USGS loc. 2820-SD. 

10-14. Acrospirifer sp. 1 (p. 47). 

Lower sandstone of Tarratine Formation. USGS loc. 2796-SD, 

Pierce Pond quadrangle, Somerset County, Maine. X 1. 

10, 13. Impression and latex replica of interior of brachial valve. 

USNM 126090. 

11, 12. Latex replica and impression of interior of pedicle valve. 

USNM 126075. 

14. Latex replica of exterior of brachial valve. USNM 126090. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 17 

2 

3 

4 

7 

5 6 

8 

10 11 

9 

I 

, , I 

J !/ I~ 

12 13 14 

ACROSPIR!FtR 
PLATE 18 

FIGURES 1-5. Acrospirifer sp. 2 (p. 48). 

Lower sandstone of Tarratine Formation. USGS loc. 2872-SD, 

Pierce Pond quadrangle, Somerset County, Maine. 

1, 2. Latex replica (X 3) and impression (X 1) of interior of 

pedicle valve. USNM 126113. 

3. Latex replica of exterior of brachial valve (X 1) . U SNM 

126089B. 

4, 5. Latex replica and impression of interior of brachial valve 

(X 1). USNM 126089A. 

6-14. Antispirifer harroldi Williams and Breger, 1916 (p. 50). 

Lower sandstone of Tarratine Formation. Long Pond quadrangle, 

Somerset County, Maine. 

6. Impression of interior of brachial valve (X 1). USNM 

126039. USGS loc. 2720-SD. 

7. Impression of interior of pedicle valve (X 1). USNN 

126040. USGS loc. 2721-SD. 

8, 10. Latex replica (X 1) and impression (X 3) of exterior of 

brachial valve. USNM 126024B. USGS loc. 2721-SD. 

9. Latex replica of exterior of pedicle valve (X 2). USNM 

126028A. USGS loc. 2722-SD. 

11. Impression of interior of brachial valve (X 2). USNM 

126034B. USGS loc. 2720-SD. 

12, 14. Latex replica and impression of interior of brachial valve 

(X 2). USNM 126034B. USGS loc. 2720-SD. 

13. Latex replica of exterior of pedicle valve (X 2). USNM 

126033B. USGS loc. 2720-SD. 

15-20. Costellispirifer perimele (Clarke, 1907) ( p. 51). 

Tomhegan Formation. USGS loc. 2750-SD, Brassua Lake quadrangle, Somerset County, Maine. 

15. Impression of interior of pedicle valve (X 1). U SNM 

126029B. 

16. Latex replica of exterior of brachial valve (X 2). USNM 

126037A. 

17. Latex replica of exterior of pedicle valve (X 1). USNM 

126035A. 

18, 19. Latex replica and impression of interior of brachial valve 

(X 1). USNM 126030B. 

20. Impression of interior of pedicle valve (X 1). U SNM 

126035B. 

21, 22. "Mucrospirifer"ci. "M." macra (Hall, 1857) (p. 6{)). 

Ventral and posterior views of internal mold (X 2). USNM 

160135. Tomhegan Formation. USGS loc. 2723-SD, Brassua 

Lake quadrangle, Somerset County, Maine. 

23- 26. Costispirifer sp. (p. 61). 

23, 25. Latex replica of exterior and impression of interior of 

pedicle valve (X 1). USNM 126023B, A. Seboomook Formation. USGS loc. 3482-SD, Spencer Lake quadrangle, 

Somerset County, Maine. 

24, 26. Impression of interior and latex replica of exterior of 

brachial valve (X 1). USNM 126018B, A. Lower sandstone of Tarratine Formation. USGS loc. 2767-SD, 

Moosehead Lake quadrangle, Somerset County, Maine. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 18 

2 3 

4 5 

6 7 

·~~ ·,> 

8 

10 

11 

12 

13 

17 

15 16 

• '. J· ~J ,'. 

. ·· \~~'1·. ' ' 

~. ·" ' ~y1\ . < :~ •• 

= )' -p_...-: I:. 

. / 

.. ' 

• f 

."J! 

18 19 

22 26 

ACROSPIRIFER , ANTISPIRIFER, COSTELL/SriRIFER, " MUCROSPIRIFER", AND COSTJSPIRIFER 
PLATE 19 

FIGURES 1-6. Megakozlowskiella sp. (p. 62). 

Beck Pond limestone. Spencer Lake quadrangle, Somerset County, 

Maine. X 2. 

1. Impression of interior of pedicle valve. USNM 126044B. 

USGS loc. 3497-SD. 

2-6. Exterior: brachial valve, pedicle valve, side view, posterior 

view, and anterior view. USNM 126046. USGS loc. 

3601-SD. 

7-11. Metaplasia cf. M. paucicostata (Schuchert, 1913) (p. 62). 

McKenney Ponds Member of Tarratine Formation. USGS loc. 

2806-SD, Pierce Pond quadrangle, Somerset County, Maine. 

7. Latex replica of exterior of pedicle valve (X 3). USNM 

126115A. 

8, 9. Impression of interior of brachial and pedicle valves (X 

4). USNM 126115B. 

10, 11. Latex replica (X 3) and impression of interior of pedicle 

valve. USNM 126115C. 

12-18. Metaplasia minuta Boucot, 1959 (p. 62). 

Tomhegan Formation. USGS loc. 2750- SD, Brassua Lake quadrangle, Somerset County, Maine. 

12. Latex replica of exterior of pedicle valve (posterior view 

X 4). USNM 126110B. 

13, 17. Impression and latex replica of interior of brachial valve 

(X 4). USNM 126086A. 

14. Latex replica of exterior of pedicle valve (X 3). USNM 

126067A. 

15. Impression of interior of pedicle valve (X 3). USNM 

126067B. 

16. Impression of interior of pedicle valve (posterior view (X 

4). USNM 126110C. 

18. Latex replica of exterior of brachial valve (X 4). USNM 

126086B. 

19-29. Plicoplasia plicata (Weller, 1903) (p. 63). 

19-28. Lower sandstone of Tarratine Formation USGS loc. 2813-

SD, Pierce Pond quadrangle, Somerset County, Maine. 

19. Latex replica of exterior of brachial valve (X 

2). USNM 126114A. 

20. Latex replica of exterior of pedicle valve (X 2). 

USNM 126087A. 

21. Impression of interior of pedicle valve (X 2). 

USNM 126087B. 

22. Impression of interior of brachial valve (X 2). 

USNM 126114B. 

23. Latex replica of interior of brachial valve (X 

3). USNM 126106. 

24, 25. Latex replica and impression of interior of 

pedicle valve (X 3). USNM 126260. 

26, 27. Latex replica and impression of interior of 

pedicle valve (X 3). USNM 126259. 

28. Latex replica of exterior of pedicle valve (X 

3). USNM 126087A. 

29. Impression of interior of brachial valve (X 3). Seboomook 

Formation. USGS loc. 2884-SD, Chesuncook quadrangle, 

Picataquis County, Maine. USNM 126256B. 

30-32. Cyrtina? cf. C. rostrata (Hall, 1857), (p. 63). 

Brachial, posterior, and side views of internal mold (X 2). USNM 

160136. Seboomook Formation. USGS loc. 2883-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 19 

7 

.f -)· .• '1, . .., 

r ' , ~ • ,, . .. t, 18 

,...,.-1,.,. . * • . . 4{ I ~ 

~·'· 

17 

19 

23 

27 

29 30 32 

MEGAKOZLOWSK!ELLA, METAPLAS IA, PLJCOPLAS!A, AND CYRTINA? 
PLATE 20 

FIGURES 1-6. Merista cf. M. tennesseensis Hall and Clarke, 1895 (p. 63). 

Hardwood Mountain Formation. USGS Joe. 3488-SD, Spencer 

Lake quadrangle, Somerset County, Maine. 

1-4. Exterior: side, anterior, posterior, and pedicle valve 

valve (partly exfoliated) views (X 1). USNM 

126105B. 

5. Impression of interior of pedicle valve (X 2). USNM 

126085. 

6. Exterior of brachial valve (X 1). USNM 126105B. 

7-13. Meristella lata (Hall, 1859), (p. 64). 

7, 8, 10-12. Lower sandstone of Tarratine Formation. Long Pond 

quadrangle, Somerset County, Maine. 

7. Latex replica of exterior of pedicle valve 

(X 1). USNM 126116A. USGS Joe. 

2721-SD. 

8. Impression of spire (X 1). U SNM 

126079A. USGS Joe. 2777-SD. 

10. Latex replica of interior of pedicle valve 

(X 2). USNM 127390. USGS Joe. 

2777-SD. 

11, 12. Latex replica and impression of interior 

of brachial valve (X 2). USNM 

126261A .. USGS Joe. 2721-SD. 

9. Impression of interior of brachial valve (X 1). USNM 

126103. Seboomook Formation. USGS Joe. 3482-SD, 

Spencer Lake quadrangle, Somerset County, Maine. 

13. Impression of interior of brachial valve (X 2). USNM 

126082B. Seboomook Formation. USGS Joe. 2884-SD, 

Chesuncook quadrangle, Piscataquis County, Maine. 

14-22. Charionoides doris (Hall, 1860), (p. 64). 

Tomhegan Formation. Brassua Lake quadrangle, Somerset County, 

Maine. 

14-16. Impression of interior of pedicle and brachial valves 

and side view (X 2). USNM 126111B. USGS Joe. 

2820-SD. 

17. Latex replica of beak of pedicle valve (X 3). USNM 

126117B. USGS Joe. 2750-SD. 

18. Impression of interior of brachial valve (X 1). USNM 

126102. USGS Joe. 2750-SD. 

19, 20. Latex replica and impression of interior of brachial 

valve (X 2). USNM 126081. USGS Joe. 2750-SD. 

21. Impression of interior of pedicle valve (X 2). USNM 

126080A. USGS loc. 2750-SD. 

22. Impression of interior of pedicle valve (X 2). USNM 

126092. USGS Joe. 2750-SD. 

23-27. Nucleospira sp. (p. 65). 

Base of Hobbstown Formation. USGS loe. 3479-SD, Spencer Lake 

quadrangle, Somerset County, Maine. 

23, 24. Impression and latex replica of interior of pedicle valve 

(X 3). USNM 126091B. 

25, 27. Latex replica and impression of interior of brachial valve 

(X 4). USNM 126262. 

26. Latex replica of exterior of pedicle valve (X 4). USNM 

126091A. 

28-37. Protathyris sp. (p. 65). 

Hardwood Mountain Formation. USGS loc. 2822-SD, Attean 

quadrangle, Somerset County, Maine. X 2. 

28-31, 33. Exterior: brachial valve, pedicle valve, posterior, anterior, and side views. USNM 126262. 

32, 34-37. Exterior: posterior, pedicle valve, side, brachial valve, 

and anterior views. USNM 126070. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 20 

8 

4 6 7 

2 

3 

11 

10 12 

13 14 15 16 17 

18 

22 

31 

24 

26 27 

25 34 35 37 

MER!STA, MER/STELLA, CHARIONOIDES, NUCLEOSP/RA, AND PROTATHYRIS 
PLATE 21 

FIGURES 1- 6. Nanothyris hodgei Boucot, n. sp. (p. 65). 

Lower sandstone of Tarratine Formation. USGS loc. 2832- SD, 

Brassua Lake quadrangle, Somerset County, Maine. 

1. Latex replica of interior of brachial valve (X 3). Holotype, 

USNM 126194. 

2. Impression of exterior (posterior view X 2). Paratype, USNM 

125943. 

3, 4. Impression of interior of brachial and pedicle valves (X 2). 

Paratype, USNM 126191. 

5. Latex replica of exterior of pedicle valve (X 3). Paratype, 

USNM 126183A. 

6. Latex replica of exterior of brachial valve (X 3). Para type, 

USNM 126220A. 

7- 13. Nanothyris cf. N. subglobosa (Weller, 1903) (p. 66). 

Beck Pond Limestone. USGS loc. 3601- SD, Spencer Lake quadrangle, Somerset County, Maine. 

7-11. Exterior: pedicle valve, brachial valve, side, posterior, and 

anterior views (X 2). USNM 126192A. 

12. Exterior of pedicle valve (X 1) . USNM 126192B. 

13. Cross section of brachial valve (X 3). USNM 126187. 

14- 17. Rensselaeria sp. (p. 66). 

Lower sandstone of Tarratine Formation. USGS loc. 2767-SD, 

Moosehead Lake quadrangle, Somerset County, Maine. X 2. 

14, 15. Impressions of interior of brachial valves. USNM 126216C, 

D. 

16, 17. Impressions of interior of pedicle valves. USNM 126216B, 

126214. 

18-30. Beachia thunii (Clarke, 1907) (p. 69). 

Lower sandstone of Tarratine Formation. Somerset County, Maine. 

18, 23-25, 29. Exterior: brachial valve, anterior, side, posterior, 

and pedicle valve views (X 1) . USNM 126198. 

USGS loc. 2813- SD, Pierce Pond quadrangle. 

19. Impression of interior of pedicle valve (X 1). USNM 

126207B. USGS loc. 2796-SD, Pierce Pond quadrangle. 

20. Latex replica of interior of pedicle valve (X 1). 

USNM 126217C. USGS loc. 2813- SD, Pierce Pond 

quadrangle. 

21. Impression of interior of brachial valve (X 1f. 

USNM 126206A. USGS loc. 2796-SD, Pierce Pond 

quadrangle. 

22. Impression of interior of brachial valve (X 1). 

USNM 126202. USGS loc. 2813-SD, Pierce Pond 

quadrangle. 

26, 30. Impression and latex replica of interior of pedicle 

valve (X 1). USNM 126200. USGS Joe. 2731-SD, 

Long Pond quadrangle. 

27. Latex replica of interior of brachial valve (X 1). 

USNM 126199. USGS loc. 2813- SD, Pierce Pond 

quadrangle. 

28. Impression of interior of brachial valve (X 3). 

USNM 126203. USGS loc. 2813-SD, Pierce Pond 

quadrangle. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 2 1 

8 

27 29 30 

NANOTHYR!S, RENSSELAER/A , AND BEACH/A 
PLATE 22 

FIGURES 1-5. Beachia thunii (Clarke, 1907) (p. 69). 

1. Impression of interior of brachial valve (X 1). NYSM 8436. 

Unname<i sandstone. Telos Lake Dam, Telos quadrangle, Piscataquis County, Maine. 

2. Impression of interior of brachial valve (X 1). USNM 126199. 

Lower sandstone of Tarratine Formation. USGS loc. 2813-

SD, Pierce Pond quadrangle, Somerset County, Maine. 

3. Impression of interior of brachial valve (X 1). USNM 126204. 

Seboomook Formation. USGS loc. 2884-SD, Chesuncook quadrangle, Piscataquis County, Maine. 

4. Latex replica of interior of pedicle valve (X 2). USNM 126205. 

Lower sandstone of Tarratine Formation. USGS loc. 2813-

SD, Pierce Pond quadrangle, Somerset County, Maine. 

5. Impression of exterior of pedicle valve (X 2). USNM 126209. 

Lower sandstone of Tarratine Formation. USGS loc. 2777-

SD, Long Pond quadrangle, Somerset County, Maine. 

6-13. Cloudothyris postovalis Boucot and Johnson, 1968 (p. 69) . 

Tomhegan Formation. Brassua Lake quadrangle, Somerset County, 

Maine. 

6. Impression of interior of brachial valve (X 2). USNM 

126210A. USGS loc. 2750-SD. 

7, 12. Impression and latex replica of interior of brachial valve 

(X 2). USNM 126218. USGS loc. 3238-SD. 

8, 9. Latex replica and impression of interior of pe<iicle valve 

(X 1). USNM 126208A. USGS loc. 2750-SD. 

10. Impression of cardinal process (X 5). USNM 126195. USGS 

loc. 2814-SD. 

11. Latex replica of interior of pedicle valve (posterior view 

X 3) . USNM 126208A. USGS loc. 2750- SD. 

13. Latex replica of exterior of pedicle valve (X 1) . U SNM 

126208B. USGS loc. 2750-SD. 

14-24. Amphigenia parva Clarke, 1907 (p. 70). 

Tomhegan Formation. USGS loc. 2750-SD, Brassua Lake quadrangle, Somerset County, Maine. 

20, 

14. Impression of interior of pedicle valve (posterior view 

X 2). USNM 126193B. 

15. Impression of interior of pe<iicle valve (X 1). USNM 

126190A. 

16. Impression of interior of pedicle valve (posterior view 

X 2). USNM 126196A. 

17. Impression of interior of pe<iicle valve (X 1). USNM 

126219C. 

18. Impression of interior of brachial valve (X 2). USNM 

126197B. 

19. Latex replica of exterior of brachial valve (X 1). USNM 

126219B. 

21. Latex replica and impression of interior of brachial valve 

(X 1). USNM 126219A. 

22. Impression of interior of pedicle valve (X 2). USNM 

126196A. 

23. Impression of interior of brachial valve (X 2). USNM 

126188A. 

24. Latex replica of interior of pe<iicle valve (X 2). USNM 

127389. 
GEOLOGICAL SURVEY 

1 

6 

8 9 

\~ f 

1:; 4 ~ .. '~ • • J; "</ 

11 

14 

19 20 21 

PROFESSIONAL PAPER 784 PLATE 22 

2 

7 

5 

13 

12 

15 16 17 

22 23 

BEACH/A , CLOUDOTHYRIS, AND AMPHIGENIA 
PLATE 23 

FIGURES 1-5. Globithyris callida (Clarke, 1907) (p. 72). 

Tomhegan Formation. Brassua Lake quadrangle, Somerset 

County, Maine. 

1. Exterior of pedicle valve (X 1). USNM 126165A. USGS loc. 

2713-SD. 

2. Anterior view of interior of shell (X 5). USNM 126180. USGS 

loc. 2713-SD. 

3. Exterior of brachial valve (X 2). USNM 12f)165B. USGS loc. 

2713-SD. 

4. Interior view of brachial valve (X 5). USNM 126180. USGS 

loc. 2713-SD. 

5. Impression of interior of brachial valve (X 2). USNM 67778. 

East side of Brassua Lake opposite inlet of Moose River. 

6-13. Globithyris diania (Clarke, 1907), (p. 73). 

Tomhegan Formation. Brassua Lake quadrangle, Somerset 

County, Maine. 

6. Impression of interior (posterior view X 1). USNM 126182. 

USGS loc. 2869-SD. 

7-lL Impression of interior: brachial valve, pedicle valve, side, 

posterior, and anterior views (X 2). USNM 126164B. 

USGS loc. 2869-SD. 

12, 13. Impression and latex replica of interior of brachial valve 

(X 2). USNM 126167A. USGS loc. 2715-SD. 

14-26. Mutationella parlinensis Boucot, Caster, Ives, and Talent, 1963. (p. 73). 

Lower sandstone of Tarratine Formation. USGS loc. 2718--SD, 

Long Pond quadrangle, Somerset County, Maine. 

14-18. Impression of interior: posterior (X 2), pedicle valve (X 

1), side (X 1), anterior (X 1), and brachial valve (X 2) 

views. Holotype, USNM 126178A. 

19. Impres.sion of interior of brachial valve (X 2). USNM 

126168A. 

20. Latex replica of exterior of pedicle valve (X 1). USNM 

126173B. 

21. Latex replica of exterior of brachial valve (X 2). USNM 

126186. 

22, 26. Latex replica and impression of interior of pedicle valve 

(X 2). USNM 126166B. 

23, 25. Latex replica (X 3) and impression (X 2) of interior of 

pedicle valve. USNM 126171. 

24. Impression of interior of brachial valve (X 2). USNM 

126185A. 

R U.S. GOVERNMENT PRINTING OFFICE' 1973 0-499-380 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 784 PLATE 23 

L 4 25 26 

GL OBITHYRIS A ND MUTA TIONELLA