No. 8.] SPENCER — GEOLOGICAL SKETCHES. 467 



longus,Stricklandia Canadensis, Spirifer radiata, S.Niagarensis, 

 Atrypa reticidaris, A, plicafella, A. ohfusipHcata, A. nitida, 

 A. nodostriata ; Avicula ernacerata, A. suhplana ; Platyostoma 

 Niagarensis, Platijceras angulatus ; Orthoceras Brontes, 0. un- 

 dulatum, 0. virgatum ; Conularia Niagarensis, and two unde- 

 termined species, one of which is eight inches long, and of which 

 only two specimens have been obtained ; Calymene Blumenha- 

 chii, Dalmanites Umulurns, Ceranrus insignis, Lichas unde- 

 termined, Ascidaspis undetermined, Biimastes Barriensis, &c. 

 Besides these, there are a number of others which have not been 

 determined, and many more quite obscure, I have obtained 

 two or three specimens of Atrijpa reticularis which are interest- 

 ing, as showing perfectly the silicified spiral supports for the arms. 



Superficial Geology. 



Between the Niagara Escarpment at Hamilton and Burlington 

 Bay, the Medina shales are covered with drift deposits. The 

 surface rises gradually to the foot of the Escarpment, which is 

 125 feet above the lake. The next hundred feet of the ascent 

 (vertical) of the slope is at a somewhat high angle, and the 

 material is largely made up of the debris of the adjacent rocks, 

 often concealing the whole of the Medina, and in some places 

 part of the Clinton also. 



The valley to the west of Hamilton, in which Dundas is 

 situated, is about eight miles long, and five or six miles wide at 

 its eastern extremity. It has been excavated by an ancient river, 

 and in form is Y-shaped, the apex being to the west. Much 

 of it is filled with irregular hillocks and broken ridges, which 

 are often separated from each other by deep ravines or by allu- 

 vial flats of considerable width. The ridges are composed of 

 blue and brown clays, sands or gravels, some of which are largely 

 made up of the dehris of the Hudson River formation, with 

 boulders of Laurentian gneisses, and also some remains of the 

 rocks of the immediate vicinity The eastern portion of the 

 Dundas valley is occupied by an extensive marsh, which is sep- 

 arated from Burlington Bay by the " Burlington Heights," 

 which are 107 feet above the lake, and consist of a narrow sprit 

 which is inade up of sand and coarse and fine gravel — being part 

 of a former shore-line. This ends abruptly at the north-western 

 part of the marsh, and between the Heights and the escarpment 

 to the north, there is a deep ravine, through which the streams 



