﻿54 JY. S. Shaler — Geology of Cobscook Bay District, Me. 



only small quantities of the rock could be detached. The 

 fossils promise to afford a series very nearly connected with 

 those in Leighton's Bay and probably of the same age but 

 representing a different association of fossils. On the west 

 shore of Straight Bay there is another set of rocks affording a 

 section over one hundred feet in thickness containing a limited 

 but peculiar fauna. 



The last of these important sections is that exhibited on 

 Moose Island, on which Eastport stands. This consists in a 

 great thickness of shales of a generally dark carbonaceous look, 

 reminding the observer, as has already been remarked, of the 

 Devonian black shale of the Ohio valley and western New York. 



The Moose Island series is rather thicker bedded than the*, 

 ordinary Devonian shale ; its upper part is composed of dark, 

 siliceous flags, with occasional interbeddings of what will prob- 

 ably prove to be volcanic ash deposits. The section as a whole 

 is decidedly like the Devonian black shale. The series, as far 

 as exhibited, has a thickness of about one thousand to fifteen 

 hundred feet, but neither its superior or inferior limits are seen. 



The Orange Bay section,, being that which is richest in its 

 fossil contents may, in the determination of these various 

 horizons advantageously be used as a datum level. If its 

 stratigraphic position can be approximately determined, the 

 other sections can then be grouped about it. This seems a 

 more feasible way of approaching the problem than by trying 

 to make separate identifications for each section in the basin. 



The following list of fossils from this last named horizon, 

 with the comments given therewith, will serve to show the 

 data which are now in hand for determining the geological age 

 of the beds. 



List of Species. 



Mollusca. 

 Orthoceras perstriatum. 



" tenui-annulatum. 



Holopea antiqua, var. 

 Platystoma depressum. 

 Platyceras lamellosum. ? 



" platystomum, var. 



Loxonema allied to L. Fitchii. 

 Anatina sinuata ? 

 Avicula allied to A. manticula. 



" " A. securiformis. 



" " A. communis. 



Megambonia allied to M. lata. 



" " M. ovata, 



Spirifer modestus?. 

 " perlammelosus. 



