32 Fossils of the Potsdam Sandstone, 



ARTICLE III. — Fossils of the Potsdam Sandstone j Sea-weeds, Shells^ and 

 foot prints on the rock at Beauharnois. 



The Potsdam Sandstone once existed in the condition of gi-eat beds of 

 gand drifted about the bottom of the ocean, forming T\-ide flat bars or banks, 

 and on the shores extensive level sea beaches. A few rocky desert islands, 

 probably of no gTeat extent, and v/ith a fierce tropical climate, alone marked 

 the position of the present continent of North America. The seas were 

 inhabited, for, in the sandstone, we find the remains of what seems to have 

 been a very remarkable aquatic vegetation, besides a few diminutive shell- 

 lish and the foot-prints of certain extinct animals, concerning whose organi- 

 zation there yet appears to be much doubt. All of these shall receive some 

 consideration in the following article : — 



1. ScomiHus Linearis. 



The fossils to which Professor Hall, the greatest of American Palaeon- 

 tologists, has given the above name, consists of numerous small straight 

 stems which penetrate the strata of sandstone perpendicularly sometimes to 

 the depth of one or two feet. Where they are abundant they have the ap- 

 pearance of a series of small pins or pegs, from \ to \ of an inch in diameter, 

 driven into the rock. They are in general cylindrical, but sometimes flat- 

 tened and even striated. As all traces of their internal structure have long 

 since disappeared, it is impossible to decide with certainty what they may 

 have been. On the margins of the existing lakes and rivers, we fi-equently 

 Dieet with localities where in the shallow water fields ef straight reeds are 

 growing with their heads above the surface. Were the intervals between 

 these to be filled with sand and be converted into rock, the strata would 

 doubtless present the appearance of those beds of sandstone which are found 

 to be penetrated by scolithus. Professor Hall considers them to be the re- 

 mains of aquatic plants. Others are of opinion that they are holes made in 

 the sand before its consolidation by worms. The fossil occurs in the sand- 

 stone in the State of New York, and also in Canada, at Beauharnois — in 

 the Township of Landsdowne, in the County of Leeds, and in several other 

 places. 



The generic name Scolithus is from the Greek " Scolax" a worm : 

 linearis Latin, linear or line-like. 



In the neighbourhood of the City of Ottawa there are frequently found 

 large boulders of Sandstone which are penetrated by similar straight tubes, 

 but of much greater dimensions. Some of these are four inches in diameter 

 and pass through rounded masses of the rock five or six feet in thickness. — 

 They resemble the trunks of small trees rather than petrified marine plants; 

 As nothing, however, remains to be seen but the straight cyhndrical stemSj 

 they cannot be referred to any particular family of the vegetable kingdom. 

 The boulders appear to be Potsdam Sandstone, but we are not aware that 

 these large fossils have yet been discovered in the undisturbed beds of the 



