The daily morning journal and courier., 1902-05-23
VOLCANIC ACTION.
MODERN THEORY EXPLAINED
 BY ". 1T. c. PYNCHON.
Three Great Eruptions in the Early History of This Region-Evidences In the Rocks.

"The Volcanic History of the Con-
 necticut Valley was the subject taken
 by w. H. c. Pynchon for the third of
 his lectures on the geological history of
 the state, given in Boardman Hall,
 Trinity college, Wednesday afternoon.
 Taking up first the main features of
 volcanic action as we understand 1t to- day, the lecturer said:
 The old theory of volcanic action was that a large mass of molten matter, imprisoned in the earth, broke forth at
 more or less regular intervals. and poured large masses of this heated
 rock upon the earth. This theory has not been greatlyimproved, and 1t is a question whether we have to-day any complete solution of the causes of VOL
 canic action. The one, however, that the process of the formation of the sed- imentary rocks on the ocean floor, quantities Of water are imprisoned in the rock. The outer layers of rock gradually blanket these lower layers, and the water, becoming heated by the earth, is held under great pressure. It seeks the weakest place in the rock and forces it's way up. The vast amount of imprisoned water becomes superheated steam, and the pressure carries every thing before 1t. The heat of the steam melts the rocks which form the tube of the volcano and this molten rock is thrown out in the form of lava. The
 chief, prominent and special feature of
 volcano then. is steam. At Martin ique, the explosion seems to have been
 caused by an earthquake, which
 opened some crack in the rock through which the steam found vent, and the imense pressure, suddenly released,
 blew off the whole top of the mountain
 The action of any volcano is shown on
 small scale by a geyser, which works
 on exactly the same principle
 In the eruption of a volcano, the
 great quantities of cinders which are
 thrown out are heaped up about the
 crater. This is shown at Vesuvius, where the ashes have formed an en- tirely new cone. As the lava wells up
 from the volcano, it rolls over the edge
 and down the side, but when the erup-
 ton is over, the lava which has not yet flowed out of the tube, does not flow
 back, but becomes a solid mass The
 erosion of the ashes in the course of time leaves this core bare and thus we have what are known as the buttes found in the western states.
 In Connecticut there are most decided evidences of volcanic action Just where the great volcano was located cannot be exactly determined, but that lit once existed is certain. There were three great eruptions in the state. The first was the smallest of the three. The
 second spread sheet of lava varying from three hundred to five hundred feet in thickness, from the coast line of the state to the northern part of Mas sachusetts, and the third was but slightly smaller in extent. The evil
 dences of these eruptions are enormous and the time by which each was sepa7 rated from the other can be approxi- mately estimated. After the last of the
 three great eruptions, the whole sur face of the land tilted to an angle of about fifteen degrees towards the east This tilting of the land brought the three layers of the volcanic rock into view, causing the sharp western faces and the long eastern slope of the hills throughout the state. The three ridges of volcanic or trap rock thus formed are called, in the order of their forma- ton, the interior, main and posterior ridges. At Meriden good illustration is shown of the main sheet, which at Chancer's Peak rises to it's full height, and shows beneath it the layer of vol canic rock which marks the first erup- tion At Lamentation Mountain Is found one of the most interesting fea- lures of the volcanic action which once took place. At the side of the noun
 tain, a large bed of volcanic ashes has been unearthed, and In the bed may plainly be seen the large blocks of rock which were at one time thrown out in half-melted state by the volcano.
 The Hanging Hills near Meriden show plainly the first and second
 sheets. and in the same way they may
 be traced through the state. The third ridge. marking the last eruption, comes lnIO DTOIlllltllCt ilttti iioi tip'N Nt "i'A forms the long ridge on which the col
 lege stands In this sheet, picture taken in the stone quarries shows the holes in the rock which were made by
 the steam formed by the hot lava flow ing over the mud of the sedimentary
 rock. The center of all this volcanic
 action seems to have been in the hills
 north of New Haven. It was probably
 from this point that the lava flowed in
 quantities which would make the erup-
 tions of Vesuvius, Aetna and Mont
 Pelee seem insignificant, when it is re-
 membered that there were three flows
 of lava, the smallest extending to the
 northern line of the state, and being
 about one hundred feet in thickness,
 and the largest reaching the northern
 line of Massachusetts, and having
 depth of five hundred feet.-Hartford
 Courant.