448 FOSSILS IN LIMESTONE. 



The position of these rocks in Bernardston may be understood from the section in Fig. 

 266, which crosses the rocks northeast and southwest, or at right angles to their strike. 



Commencing at the southeast end of the section we find a small knob of distinct clay 

 slate, with a strike of N. 52 E., and a dip of 30 E. It is thicker bedded and harder than 

 most clay slate. This is at A. Before reaching the limestone we pass over, at band C, 

 quartz rock and quartzose conglomerate. The first ledge west of A, has the strike N. 65 

 E., and dips 29 E. Still further west, at a quarry where the quartz rock is very much 

 divided by joints, the strike is N. 50 E., and the dip 25 E. A few rods south of the 

 limestone this quartz rock is mostly hyaline, and has the strike N. 60 E., and the dip 

 52 E. Twenty rods north of the limestone, quartz rock, which we suppose to be the 

 same as C in the figure, dips 60 W. Hence we have sometimes doubted whether the 

 true position of the limestone is given in the figure. 



This quartz rock is very distinctly stratified with some mica interlaminated, and is 

 often jointed. It extends northeasterly into and through Vernon, but nowhere, save in 

 Bernardston, have we found any clay slate overlying it, as at A. The great body of the 

 slate lies to the west and below the quartz. The quartzose conglomerate at B is some- 

 what insulated from the other rocks, but its relative position to the others we suppose to 

 be correctly represented. The semi-crystalline limestone, F, which is the most important 

 rock upon the section, is both overlaid and supported upon very thin bands of clay slate, 

 each not more than from four to six feet in thickness. The limestone is more than ten 

 feet thick. The rock is highly crystalline, and so are the fossil remains. The larger 

 relics have an annulated appearance, but the specimens are largest at one extremity, 

 and sometimes an inch in diameter. They are obscure. Perhaps they belong to the 

 Cyathophylloid family of corals. But there is a small species of encrinite present, 

 concerning whose nature there is no question. This limestone embraces a bed of mag- 

 netic iron, some of which has passed to the condition of limonite, not differing in appear- 

 ance from bog ore. The limestone runs northeast and southwest, dipping 16 S.E. It is 

 composed of carbonate of lime, 98.38 ; peroxyd of iron, 0.62 ; and silica, 1.00. 



Only a few rods N.W. of the limestone there is a rock made up of fragments of quartz 

 and slate, whose position seems to be this : strike, N. 5 W., dip, 25 W. A little further 

 there is a slaty, dark-colored quartz rock, with the same position. Next there is a ledge 

 of quartz rock, J, dipping east. The length of the section thus far is about eighty rods. 

 Nearly a mile west of the limestone clay slate shows itself, running N. 3 W., and dipping 

 60 E. No rock shows itself between, but we have extended the clay slate nearly to J, 

 because from other sources it is known that this rock occurs here. This band of clay slate 

 is several miles wide, and is the range which enters Vermont in Gruilford and Vernon. 

 A few rods southeast of the section, the Connecticut River sandstone appears, Avith a 

 westerly dip. 



Professor James Hall has examined the fossils from this bed of limestone, and finds 

 them to resemble the large encrinites of the upper Helderberg group of New York. He 

 thinks that this limestone is certainly no older than upper Helderberg, and yet that the 

 encrinal remains, though unique, are not sufficiently characteristic forms of life to be in- 

 fallible guides in the identification of strata. 



The reason why we have little doubt of its Devonian character, is its stratigraphical 



