



'y^ 

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120 Scientijic Intelligence, y ^«|. 



mitted that the Green Mountains are not Taconic but Silurian roclcs, 



there is no reason why we should not refer them simply to the age of 

 the Alleghanies, the more so as we have direct evidence in the raised 

 conglomerates o? Massachusetts, that at least some of the ridges of 

 New Enf^land are not of an earlier age than the coal formation. 



How far this reasoning might apply to the many other regions con- 

 nected by Mr. Beaumont with tbis supposed oldest Meridional system, 

 Mr. Desor was unable to say, but observed, that with all due regard for 

 the great abilities of his illustrious teacher, he thought there was no 

 sufficient reason for upholding any longer this peculiar system, unless 

 it be established on better proofs. 



In removing thus this so-called oldest Meridional system from its 

 prominent place, it is not a little interesting to notice that those ranges 

 of hilis and mountains which are actually known to have been raised 

 previous to the deposition of the oldest fossiliferous rocks, such as the 

 primitive mountain ranges on the north bank of the St, Lawrence, the 

 granite ranges of Lake Superior, and the iron-bearing old slates of that 

 country are all more or less parallel to the equator. It would seem as 

 if in these early times, there had been a prevailing disposition on the 

 part of the earth crust Xo wrinkle in that direction. (We take it for 

 granted that these old hills are the result of a shrinkage in consequence 

 of the cooling of the earth's surface rather than a positive upheaval.) 

 It is only at a later period that we meet with wrinkles running in the 

 opposite direction (north and south). 



2, Loicer Silurian Reptile in Canada^ (From LyelPs Anniv. Ad- 

 dress before the Geo). Soc. of London, Feb., 1851, p. 59.)— I bave 

 not alluded in this Address to tlie recent discovery of the track of a 

 quadruped imprinted on a lower silurian sandstone in North America, 

 We are indebted to Mr. Logan, now at the head of the Government 

 Survey" in Canada, for having carefully determined the position of the 

 rock containing it. The locality is the village of Beauharnois, on the 

 south side of the St. Lawrence, twenty miles above Montreal. The 

 rock, a fine-grained whitish sandstone, quarried for building, belongs 

 to the group called the Potsdam sandstone by the New York surveyors, 

 and lies at the base of the whole fossiliferous series of North America- 

 The markings were first pointed out to Mr. Logan by Mr. Abraham, 

 editor of the Montreal Gazette, who appreciated their geological im- 

 portance. Assuming the Chelonian origin of these foot-prints, they 

 constitute the earliest indication of reptile-life yet known, and are not 

 only anterior to the most ancient memorials of fish hitherto detected, 

 but agree in date with the first known signs of well-defined organtc 

 bodies, such as Ling:uliE, met with in the same rock. Professor Owen, 

 of the Colleore of Surgeons, has examined a slab of the sandstone, on 

 the uppe.r surface of which the foot-prints are impressed, together witn 

 a plaster cast of the remainder of the continuous trail, in all 12^ k^^ 

 long, brought to London by Mr. Logan ; and the Hunterian Professor 

 has had the kindness Xo communicate \q me the following description. 



"The impressions are more numerous in regular succession than 

 any that have been previously discovered ; so that the evidence oi 



* R, Owen— Letter to Sir C. Lyell, March IStli, 1S51. 



