1869.] WALLBETDGE CAIfADA WEST. 263 



2. Post-Tertiary. — Neglecting the recent formations, wHch. are 

 of local occurrence only, the surface of the county is for the most 

 part covered by an extensive accumulation of sand, gravel, and clay, 

 with boulders of northern rocks, forming a portion of that general 

 covering of drift which overlies the greater portion of the province, 

 and extends southwards into the United States. The upper part of 

 these deposits consists of a series of sands, gravels, and clays, more 

 or less distinctly stratified, and usually resting upon a tenacious 

 unstratified Boulder- clay. The boulders are derived partly from the 

 syenitic, gneissoid, schistose, and limestone rocks of the northern 

 Laurentian area, and partly from the wreck of the thick-bedded 

 limestone, which will be subsequently mentioned as forming a 

 part of the Trenton group, and which, previously to its denuda- 

 tion, overspread a great portion of the Laurentian rocks of the 

 northern townships of Hastings. Many of the blocks have a volume 

 of several cubic yards each, and are often broken up for road-metal. 

 A single boulder or ice-borne mass of Laurentian rock, at the 

 Shannonville Station on the Grand Trunk Railway, covers a super- 

 ficial area of about 5 acres, and has a thickness of 100 feet. Iso- 

 lated boulders are not unfr equently found on the tops of hills, where 

 they have probably been left by the denudation of the deposit in 

 which they were originally imbedded. 



The accumulations of drift are sometimes heaped up in isolated 

 hillocks, or in ranges of hills, and sometimes spread out over the 

 valleys. A cutting in the Court House Hill, in Eelleville, exposes 

 a good section of the drift. Upon a base of Trenton limestone, the 

 surface of which is highly polished and grooved, there is an accu- 

 mulation of deposits attaining an aggregate thickness of about 60 feet, 

 and consisting below of a tenacious Boulder-clay, overlain by a thick 

 bed of blue clay and a series of finely stratified sands and gravels. 

 In the blue clay there frequently occurs the cast of a peculiar or- 

 ganism, supposed to be a plant, which presents either a ramified or 

 a lenticular form and attains a size of from 2 to 3 inches in diameter, 

 and from 1 to 1^ inch in thickness. 



A succession of deposits, similar to that exposed at the Court 

 House Hill, may be seen in the Oak Eidge — a range of drift-hills 

 running across the country from East to West, having a width of 

 from 3 to 6 miles, and varying in height from 100 to 500 feet. 



On removing the superficial accumulations, the subjacent rock, 

 whether gneiss, schist, or limestone, usually exhibits distinct traces 

 of having been subjected to glaciation. Many of the rocks are 

 highly polished, whilst others are distinctly striated and grooved, 

 the general directions of the markings being from ]S^. E. by N. 

 to S. "W. by S. Some remarkably distinct ice-scratches were ex- 

 hibited in the town of Belleville in the autumn of 1864, when a 

 cutting was made in Pinnacle Street. The section exposed about 

 30 feet of " hard pan," or gravel, with boulders of calcareous and 

 syenitic rocks, resting on the Trenton limestone. The surface of 

 this limestone, when freshly- exposed, was most distinctly polished 

 and striated, the general bearing of the marks being N. 35° E. and 



