74 



colours in extended thin broken bands of grit containing (nay 

 even almost formed of) very numerous casts of Turritella 

 Aiding® (Tate), several bivalves, &c, and alternating with, bands 

 of marl, clay, sand, &c, of about equal, but sometimes larger, 

 dimensions, viz., varying between a few inches to a foot and 

 a half, as partially illustrated by figs. 4 and 5, outline sketches 

 of part of the face of the cliff between Rogue's and Muloo- 

 wurtie Points. For fossils the immediate neighbourhood of 

 Ardrossan has been well examined, and casts and impressions 

 of a limited number of molluscs obtained, viz., Turritella Aiding ce 

 which occurs in immense profusion, and its casts (frequently 

 found delicately moulded in hyaline quartz, resembling fairy 

 corkscrews), sometimes form the largest portion of a rock 

 specimen ; other univalves, occurring rarely, are species of 

 Voluta, Cassis, Natica, Gypreea, Dentalium. Of bivalves several 

 species of Pecten, (Jhione, and Pholas. JPolaster, and one or two 

 of other species, a cast of Pentacrinus (small), and numerous 

 fragments of Eschara and Retepora nearly exhaust the list. 

 An impression of a leaf of some dicotyledonous tree (Cinna- 

 momum probably) and three specimens of fossil wood of as 

 many species complete the catalogue of vegetable remains 

 found. 



These "Turritella grits" seem to occupy a narrow strip along 

 the coast, having been observed only for about one mile to one 

 and a half miles inland, occupying everywhere the position 

 illustrated in figure 2, viz., at or near the hilltops from a point 

 a little south of Ardrossan to near Clinton, where it was 

 observed at a single place, but not ascertained whether extend- 

 ing farther north ; while below the line of sea level, at a place 

 further south, near Rogue's Point, it emerges at a low angle 

 (two or three degrees) from below this level (fig. 4) under- 

 lying the Ardrossan clays and gravels. The only way this can 

 be explained appears to be that during the close of the deposi- 

 tion of the local Tertiaries, and preceding or during that of the 

 Ardrossan clays, an upheaval of the northern part of Torke's 

 Peninsula took place which did not affect the region extending 

 to the south of Rogue's Point. The Turritella grits occur at 

 Ardrossan, apparently above a f elspathic sandstone. This rests 

 upon marbles, which are succeeded by undoubtedly Palaeozoic 

 rocks, finally abutting upon a granite which extends — to judge 

 by the character of vegetation — to within two miles of Mait- 

 land, where the gneissic rocks and the same felspathic sandstone 

 again appear. 



Mioloowurtie Clays. — The succeeding layers to the " Turritella 

 grits" appear to be absent at Ardrossan, except the next under- 

 lying it, which on account of the difference of level between 

 the upper observed surface of the sandstone mentioned (to be 



