14 Mesozoic and Ccenozoic Geology and PalmontoJogy. 



Pterozamites gracilis, P. ohtusus, P, linearis, P. spatulatus, Dioonites 

 linearis, Strangerites planus, Pterophyllum rohustum, JSFoeggerathia 

 striata, Comephyllum, eristatum, Amhlypteius ornatus, Eahdiolepis 

 speciosus, 3Iicrudi(s Icevis, Pala'onornis struthionoides, and Promath- 

 erinm silvestre, the most ancient mammalian remains yet found upon 

 the continent. 



In 1857, T. A. Conrad* described, from the Triassic black shale at 

 Phoenixville, Pennsyh^ania, 3Iyacites pennsylvanicus. 



In 1858, Meek and Haydenf described, from the Jurassic of the 

 Black Hills, Pentacrinus asteriscus, Lingxda brevirostra, Avicula 

 tenuicostata, Mytilus pertenuis. Area inornata, now Grammatodon 

 inornatus, Panopma subellijJtica, now Myacites subellipticvs. Am- 

 monites cordiformis, A. henryi, and Belemnit.es densus. 



Prof. Hitchcock made his report on the I(;hnolog.v of New England, 

 being " A report on the Sandstone of the Connecticut valley, especially 

 its Fossil Footmarks, made to the government of the Commonwealth of 

 Massachusetts." This work contains a bibliography of Nortli Ameri- 

 can Fossil Footmarks; the history of the discoveries of the tracks; a 

 discussion of the geological position of the Connecticut river sand- 

 stone, and the evidences tending to prove the Jurassic Age of at least 

 the upper half of the strata, with geological sections across the valley, 

 showing that in general the dip is easterly, varjdng fron 5° to 50°. 



The sandstone of the Connecticut valle.y extends from Northfield, 

 in the Northern part of Massachusetts, across the latter State, and 

 Connecticut to Long Island Sound, a distance of 105 miles. The great- 

 est width is at the mouth of the Farmington river, though Hitchcock's 

 Springfield section was taken where the width is nearly as great. 

 Several ranges of trap rock (greenstone, amygdaloid, and volcanic 

 grit), traverse the sandstone longitudinally, having for the most part a 

 northeasterly trend, and being generally in the form of interstratified 

 beds or masses. Along the west side of the valle.y, tliere is a coarse, 

 thick-bedded sandstone, whose prevailing color is red, but which is 

 sometimes mottled, and near the trap and the hypozoic rocks, some- 

 times nearly white. This sandstone underlies the trap. Immediately 

 above the trap, on the east side of the valley, the rocks consist of inter- 

 stratified red and black shales, volcanic grit, micaceous sandstone, 

 compact, fetid blue and gray limestone, and in some places coarse sand- 

 stone and conglomerate. It is in the shales and sandstones lying im- 



■•' Proc. Acad. Nat. Sci., vol. ix. 

 t Proc. Acad. Nat. Sci. 



