GEOLOGY AND MINERALOGY. 317 



feet, as estimated by Sir W. E. Logan. They rest on Upper Silurian rocks, and 

 underlie the Carboniferous conglomerates ; and some beds contain Lower Devonian 

 brachiopods, &c. 



Among the vegetable remains determined by Dr, Dawson is a curious genus 

 termed by him Psilophyton, which belonged to the Lycopodiacece, [and was related 

 in some respects, according to the author, to the modern genus Psilotum]. It had 

 minute ad-pressed leaves on slender dichotomously-branching stems, with circinate 

 vernation, and springing from a horizontal rhizome which had circular areoles 

 with cylindrical rootlets. Some of the shales are matted with these rhizomes, 

 Obscure traces of fructification are observable in cuneate clusters of bracts. The 

 fragments of the different parts of this interesting plant might easily be mistaken 

 for portions of fucoids, or of other and very distinct plants, such as Karstenia. 

 Halonia, Stigmaria, Schizopteris, Trichomanites, &c. The author describes two 

 species of Psilophyton, P. princeps and P. rohustus. Dr. Dawson further 

 described a new form of Lepidodendron {L. Gaspeanurri) ; also some specimens of 

 coniferous wood related to the Taxus (^Prototaxites Logani), and some less clear 

 forms belonging to Knorria, Foacites, &q. The author also noticed the occurrence 

 of Entomostraca (Beyrichia), Splrorbis, occasional fish-remains, some brachiopods, 

 and also rain-marks and ripple -marks in these Devonian beds." 



Professor Dawson has also communicated to the Geological Society a paper of 

 much interest, on "the Vegetable Structures" in Coal, an abstract of which will 

 be found in the April number of the Philosophical Magazine. 



POST-TERTIARY DEPOSITS OF THE ST, LAWRENCE VALLEY. 



In the last number of the Canadian Naturalist, Professor Dawson makes some 

 further additions to our knowledge of these interesting deposits, and figures many 

 new forms of Bryozoa and Foraminifera obtained from them. Taken in connexion 

 with the author's former researches on this subject, the present paper will be 

 found of no ordinary value to the student of Canadian Geology. The following 

 extract conveys some additional information respecting the well-known Beauport 

 beds: '' I visited this celebrated deposit for the first time last autumn. At first 

 sight it consists of a mass of stratified sand and gravel, equivalent to the Saxicava 

 sand of Montreal, and resting on boulder clay. The overlying mass is filled with 

 Saxicava, Tellince, &e. ; and the underlying boulder clay as usual contains no fossils. 

 My experience in the Montreal deposits, however, led me to expect a bed, however 

 thin, representing the Leda clay, between these ; and on searching at the junction 

 of the two great beds above mentioned, I was gratified by finding a layer of sand 

 about three inches in thickness, filled with the rarer shells of the deposit, charac- 

 teristic of its deeper waters, such as Fusus tornatus, Pecten Islandiciis, Buccinum 

 ciliatum, Modiolaria discors, &c.* The Rhyneonella psittacea occurs only in this 

 layer, and in such a manner as to leave no doubt that it is buried here in situ, in 

 the very spot where it lay anchored to the stones of the surface of the drift. On 

 these stones, however, I found a new and interesting field for observation. In the 

 thin layer above referred to, all the stones, as well as those that lay on the surface 



* Sir C. Lyell notices the fact that these shells are more abundant in the lower part of the 

 mass than above. 



