No. 4.] CHALMERS — SURFACE GEOLOGY. 201 



banks of streams some distance from the coast. In the Resti- 

 gouche valley they are found as far up as the mouth of the 

 Upsalquitch containing shells of Mya and Macoma, but have not 

 been detected on the higher lands of the interior. These clays, 

 which, so far as I can judge, are equivalent to the Leda clays of 

 the St. Lawrence valley occur usually as thin fragmentary sheets 

 in the greater part of the district under examination, but at the 

 mouths of the Nepisiguit, Tattagouche and Jacquet rivers, and 

 some other places, they form local beds of considerable extent 

 and depth. In cuttings along the Intercolonial Railway', sections 

 of these clays were exposed during its construction, and excellent 

 facilities afforded for studying them and collecting the fossils 

 embedded therein. In some of the thicker beds, as at Tatta- 

 gouche and Benjamin rivers, there are evidently upper and lower 

 clays, such as have been recognised by Mr. Matthew in the south 

 of the Province, and by Dr. Dawson in the St. Lawrence valley. 

 The lower division is sometimes a finely laminated blue clay, the 

 laminae not distinctly visible, and it is usually without pebbles. 

 In other places it is a stiff, dark gray, or brown clay, more or less 

 pebbly and unfossiliferous. The upper division is generally a 

 gray or brown clay, with the higher strata occasionally bluish or 

 black, and prolific in fossils. It likewise contains pebbles and a 

 few scattered boulders, and there are numerous proofs of its 

 upper surface having been eroded by currents, and in some parts 

 perhaps by tidal waters previous to the deposition of the over- 

 lying stratified sands. In many places, however, no well marked 

 division between upper and lower beds has been detected, and 

 the differently constituted clays graduate into each other and 

 appear to have been closely consecutive in formation, their color 

 and composition depending largely upon the nature of the rock- 

 formation or drift beds whence they were derived. For example, 

 at the mouths of rivers running through a limestone district 

 blue calcareous clays prevail, while reddish clays are invariably 

 met with in districts in which red Lower Carboniferous sandstones 

 occur. In localities where the clays overlie kame deposits they 

 are so thickly packed with boulders and material derived from 

 the latter as to be scarcely distinguishable were it not for the 

 contained fossils. 



The entire thickness of the Leda clays, upper and lower, where 

 they have their greatest development, as in the neighborhood of 

 Bathurst, is about 75 feet, and on the banks of the Tattagouche 

 ToL. X. K 2 No. 4. 



