65 



no great distance, in fact, from the pre-existing quartzites and 

 granites of the neighbourhood, Most likely we behold in them 

 only a small remnant of once extensive deposits, the less 

 coherent portion having been entirely swept away while 

 emerging from the sea, to begin the long period of its subaerial 

 existence, and when again submerged at the inauguration of 

 the Tertiary period ; for under these conditions denuding 

 agents would act most vigorously. 



To the absence of later Palaeozoic and all Mesozoic rock in 

 the Peninsula and the whole southern portion of the province 

 is also owing the absence of coal, denoting that either the 

 condition for the formation of " black diamonds " never existed, 

 or that the latter were afterwards entirely removed. The 

 former seems to me to be the more probable reason of the 

 two. The sporadic announcements by the papers of " dis- 

 coveries " of coal therefore only produce a dubious smile of the 

 practical geologist. Our PabTozoic rocks may yield (jraphite, 

 and the Tertiaries lignite ; but before the existence of charac- 

 teristic rocks is proved, the search for " real " [coal will be 

 nothing but waste of energy and money. 



During this long era the land assumed, through erosion, much 

 of its present aspect ; gorges and gullies were cut into the 

 rocky deposits and widened into valleys, as we see them at 

 present. Thus, for example. Horse Gully was cut out through 

 about 250 feet of the very dense Parara limestone, and the 

 Ardrossan sandstone almost entirely removed. 



At last the change came. Elevation ceased, stability turned 

 into depression. The advancing waves swept gradually all the 

 accumulated debris off the rocks into the gulfs, and then 

 attacked them till they sank below their influence. Thus, it 

 seems to me, the escarpments of the hills south of Ardrossan 

 mark the shore line of cliffs of this time. The solid layers of 

 sandstone were undermined till gravity overcame the cohesion 

 and huge fragments fell down to lower levels, where we see 

 them now strewn in irregular heaps and at incongruous levels. 

 The debris was carried out to sea and re- arranged along the 

 retreating coast as gravel, sand, and mudbanks. Thus we find 

 rolled grains of all the rocks of the region, even pebbles of the 

 Silurian limestone, included in the various deposits, viz., clays, 

 marls, and grits. 



The lowest local deposit, the yellow Muloowiu'tie clays, with 

 its predominating bivalves, Ostrea, Waldheimia, &c., implies a 

 comparatively deep sea ; the grits a shallo*ver one, i.e., nearer 

 to the land, which is also borne out by the great prevalence of 

 its characteristic fossil, TurriteJla Aldingce, Tate. The grits 

 consist of thin layers of an opaline silica, alternating with 

 arenaceous clays and marls. The lime of the fossils has been 



