200 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 24, 



the subjacent gneiss. From Beauharnois the rock has been traced in 

 New York in a nearly straight south-west Une, and at a distance of five 

 to thirty miles from the south-east bank of the St. Lawrence, to Ham- 

 mond and Alexandria on that river. Crossing the river then to Brock- 

 ville, it was last summer followed in Canada through the Johnstown 

 and Bathurst Districts in a tortuous course to the townships of M'Nab 

 and Nepean on the Ottawa ; and on this river it has been seen again 

 once, below Bytown, trending to a junction with the exposure on the 

 Riviere du Nord. Between Mont Calvaire and the Bathurst District 

 it may thus be considered to form the perimeter of a peninsula- 

 shaped area, the isthmus to which, between the exposures at Mont 

 Calvaire and Riviere du Nord, is about ten miles wide. Around the 

 whole of this peninsular space the sandstone rests upon the gneissoid 

 metamorphic rocks, and it is succeeded by an interior zone of cal- 

 careo-arenaceous beds, bearing the fossils which characterize the Cal- 

 eiferous Sand-rock series of New York. Within this is another zone 

 consisting of limestone corresponding in a considerable degree in its 

 fossil contents with the Chazy Limestone ; the organic remains of a 

 large area in the centre can be identified with those of the Bird's-eye, 

 Black River, and Trenton Limestones, and resting on the latter a 

 trough of the Utica Slate with its characteristic Trilobites and Grap- 

 tolites extends from Bytown some distance eastward. This concentric 

 geographical arrangement of the rocks, even without the evidence of 

 the dips, leaves little doubt that the more organic formations rest 

 on the sandstone. Where the dips are appreciable, they give a 

 general confirmation of this ; but they are for the most part small, 

 and strata over large areas have often to the eye the appearance of 

 being quite flat. The east side of the Beauharnois tongue of sand- 

 stone is bounded by the same succession of formations. 



The sandstone in Beauharnois County and the neighbouring part 

 of the State of New York is from 300 to 700 feet thick. In the 

 lower part it contains many beds of conglomerate with quartz-pebbles, 

 and it has some red layers ; but towards the top it becomes a fine- 

 grained, hard, white sandstone, and at the summit it is interstratified 

 with calcareous layers forming a passage to the rock which overlies 

 it. In this part it is abundantly marked over considerable surfaces 

 by what the geologists of New York have called Scolithus linearis, 

 which consists, where the rock is weathered, of straight, vertical, 

 cylindrical holes, of about an eighth of an inch in diameter, descending 

 several inches, and, where the rock is unweathered, of corresponding 

 solid cylinders, composed apparently of grains of sand, cemented by 

 a slightly calcareous matrix, more or less tinged with peroxide of iron. 

 Mr. Hall and other American geologists include them among the 

 Fucoids of the rock, but they appear to me more like Worm-holes. 

 In one or two instances I have perceived that the tubes are inter- 

 rupted in their upward course by a thin layer of sand, of a portion 

 which descends into them and stops them up ; and from this it 

 would appear that the cylinders were hollow when the super- 

 incumbent sand was spread over them. Whatever may be the origin 

 of the tubes, they strongly mark many beds in the upper part of the 



