Bisbee daily review., 1904-02-21
Copper Deposits
 IN TAE
 Warren District
SECOND PAPER ON SUBJECT BY
 r.l. HANDSOME.
Writer Presents, in Condensed Form, Saiiens Results of Detailed oeolog- ,eai Study of eisoee Quadrangle, Which Work Was Carried on During the Year 1902.

Below is presented the second paper by r. L. Ransome, on the geology and copper deposits of Bisbee, Ariz.. the first paper having appeared in The Daily Review of February 13:
 (Written by F. l.. Ransome for the Mining and Scientific Press)
 Post-Carboniferous Faults and In arusions-At some time during the ir ierval between the close of the car Aeniferous and the opening of the ere toceous, the long-continued subsistence and seaimentation of the region were interrupted by extensive faulting probably connected with uplift. The tauits were mostly of the normal type but there was also some reversed or everthrust faulting that may have been slightly later than the prevalent normal faulting Following the fault inig came intrusions of granite mag aa. which soiidified as granite. granite porphyry and rhyolite. These intru- sfons took the form of dikes following fau,t Assures. of sills injected between ~sedimentary beds, and of irregular stick-like masses. The dikes are well shown along the southwest face of Escabrosa ridge, west Of Bisbee. The larger intrTsions are exemplified by abe granite mass of Juniper flat, which iS inolosed in Pinel schists and ey the smaller body Of mineralized and altered porphyry forming Sacra- mento hin, just southeast of Bisbee and intrusive into Pinal schists and pafeozoic limestones. The latter mass Is of particular significance from its connection with the principal copper %eDosits of the district. The intru- aion Of the porphyry of Sacramento nill was accompanied and followed by contact metamorphism, involving the sniroduction of much disseminated sron pyrite into the adjacent paleozoic siOn of the latter into fine-grained az gregates of calcite, tremolite, wollas- &Onite. garnet, schlorite and quartz. The metamOrDhic minerals, with the excention of the pyrite. are never con- snicuously developed, and can usually @e identified only in microscopic sec s5ons.
 After the intrusion Of the granite DOrphyry, the region was eroded until Ehe opening of cIetaceous time. It is Rrobable that the primary mineraliza- Uon cf the district followed closely up- stn the eruption of the porphyry, ana Ous dates from early mesozoic time.
 The Mesozoie Sedimentary Series At the beginning of the cretaceous the gegien again began to subside, and was deposited by the ad- Iancing sea over the eroded surface n the pre-cambrian and paleozo;c cocks, with their intruded masses of sorphyry. This conglomerate is the Nasal member of the Bisbee group, an yrising four formations. These are n ascending order G) the glance con alomerate, @ the morita formation, @) the mural limestone and (4) the eintura formation.
 In places the glance conglcmerate was laid down to a uniform thickness af about seventy-five feet over an even surface, but elsewhere it is found fill ing bollowsa5 Tn a pre-cretaceous hilly Topography and attaining local thick ness of over 800 feet. The pebbles ure composed chiefly of schist, al 0hnugh those of limestone and granite Poruhyry are not entirely absent. Vsth the continued subsistence of the seeion the morita formation, compris- Ing about 1 800 feet of unfossiliferous etandstones and shales, with occasion a lenses of sandy limestones. accumu- lated above the basal conglomerate. Couformabiy overlying these is the Uu-al limestone. about $50 feet in Sb'ctness. containing abundant fossils characieristic of the Comanche divi- sion of the cretaceous. Most of these 4imestones. particularly the lower ke"s are thin-bedded and impure; but s,ard gray. massive beds, aggregatine fc-'v feet in thickness. occur near the n'a.sle of the formation and form a c.FT that is conspicuous topographic fe>+rre Of the hills north and east oi Pfehee The mural limestone is con fo-nab'v overlain by the cintura form atson, more than 2,000 feet in thick uass and consisting of alternate sand t.fo-as and shales, much like those oc czwring in the morita formation Trnee cintVda beds of the Bisbet gTrup are the youngest stratified rocks e~-osed in the Pisbee quadrangle. A. ftA'r upper surface is everywhere ons of erosion, their original thickness il unknown. The foregoing cretaceoul
 fContinued on Page Seven.)