from as limestone of the original Taconic. 245 



The limestone of this belt is mostly a gray, fine-grained crys- 

 talline rock, varying to whitish on one side, and to blackish, 

 faintly crystalline, on the other. Short lines and blotches, sug- 

 gestive of fossils, are common in its grayer portions, but distinct 

 forms I had failed to find. Hope was renewed during the past 

 winter by receiving, from Mr. D. Clark, of Tyringham, a piece 

 of obviously fossiliferous limestone labeled "West Stock- 

 bridge." Ii led to an unsuccessful search in that town in 

 which I was aided by Prof. Dwight of Poughkeepsie. On his 

 return homeward, Prof. Dwight continued his search in Canaan, 

 1ST. Y., the next town west, and there he had success. This 

 careful investigator found fossils in the limestone at two local- 

 ities, one at the railroad lunnel, southeast of Canaan Center, 

 and the other, half a mile to the south, in a feebly crystalline 

 blackish variety of the limestone. I was shortly afterward in 

 Canaan for further search and study of the rocks, and also at 

 other times later; and I discovered evidences of fossils also in 

 the limestone in place two miles east of Canaan Center, on the 

 farm of E. S. Hall, but none as distinct as those of the locali- 

 ties first visited by Prof. Dwight. 



Prof. Dwight by slicing and polishing has brought to light 

 several determinable species, notwithstanding the metamorphism 

 of the rock. The paper following this contains the results of a 

 careful study of them by himself and Mr. S. W. Ford ; and Plate 

 VII, illustrating it, shows at a glance, that this Taconic lime- 

 stone is not pre-Cambrian or Cambrian. The species include 

 remains of Murchisonias, Pleurotomarias, Crinoids, Fenestellse, a 

 Trilobite, and probably of Brachiopods; and multitudes of frag- 

 ments not determinable. From the fossils, these authors are 

 led to refer the limestone, that is, the part of it affording the 

 fossils, probably to the Trenton period. 



Two of the localities affording fossils occur in the main belt 

 of trie limestone, where it is half a mile to a mile wide, and the 

 third (the locality at the railroad tunnel) in a limestone area on 

 the west side of an isolated belt of schist or slate, which con- 

 nects with the main belt two miles north, near Queechy ; and 

 they are all within two miles of the Massachusetts boundary 

 and a mile or less from the schist of the Taconic range. The 

 distribution of the areas and the positions of the localities will 

 be given on the map of Middle and Northern Berkshire which 

 I shall soon publish in this Journal. 



At the railroad tunnel the limestone dips eastward at a small 

 angle (15° to 20°) beneath the slates; and the locality that has 

 afforded the fossils is hardly 200 yards from the overlying 

 slates on the east and south. Both of the localities found by 

 Prof. Dwight are very near this isolated ridge of schist, that 

 of the tunnel limestone on the west of it, and the other ledge 



