698 J. W. JTJDD ON THE SECOKDAKY ROCKS OE SCOTLAND. 



their fossil contents. Instead of the thin beds which occupy this 

 horizon in England, we find thick masses of limestone alternating 

 with estuarine strata, the former resembling the equivalent beds of 

 "Western France, the latter those of Scania. Unfortunately the 

 complete series of the beds and their relation to the overlying de- 

 posits cannot be traced in any one continuous section, and the 

 fossils, though numerous, are enclosed in so hard a matrix as to be 

 very difficult of extraction. At the burn called Allt-Breugach and 

 in a tributary stream a tolerably good succession of the strata can, 

 however, be made out. The remarkable relations of this singular 

 patch of Jurassic strata, and the curious combination of circum- 

 stances to which it owes its preservation, have been already com- 

 mented on, and are illustrated by the plan and section (fig. 3, p. 672). 

 Where the Cambrian sandstones are faulted against the calcareous 

 beds of the Infralias the line of junction is very well marked, the 

 copious streams which flow over the first-mentioned rocks being 

 immediately lost in swallow-holes on reaching the latter. 



The succession of strata of Infralias age at Applecross is as fol- 

 lows (in descending order) : — 



ft. in. 



(1) Oolitic limestone with Cardinia coneinna and other shells, with 



beds of shelly limestone below crowded with Ostrea irregularis . 50 



(2) Alternations of limestones with calcareous grits and shales, and 



occasional beds of Oysters. 



(The thickness of (2) is considerable, but could not be exactly 

 determined.) 



(3) Great series of sandstones, grits, and conglomerates with coal- 



seams, exhibiting clear evidence of shallow-water and estuarine 

 conditions. This series is about 30 ft. thick, and exhibits the 

 following members in the Allt Breugach : — 



a. Thick -bedded sandstone and grit (occasionally calcareous), 

 forming a well-marked escarpment at the highest point at which 

 the Jurassic beds are exposed in the Allt Breugach. The only 

 fossils found were fragments of a gigantic Pinna near the base 



of the bed 11 



b. Bed of conglomerate with scattered pebbles of white and pink 

 quartz 9 



c. Masses of sandstone similar to a, but generally more thinly 

 bedded, passing into soft occasionally ferruginous sands on the 

 one hand, and into fissile sandy beds on the other. These fos- 

 sil beds contain spines of Acrosalenia and Cidaris, ossicles of 

 Pentacrinus, and small univalves. Some others among the beds 

 pass into a coarse calcareous grit, while in portions of the mass 



small quartz-pebbles are found abundantly scattered 12 



At one point in this series of beds an inconstant seam of coal, 

 of good quality but only an inch or two in thickness, was ex- 

 posed in 1872, when I first visited this section. 



d. Thick bed of hard sandstone passing into calcareous grit, 

 pebbly in places, and containing a few shells of Ostrea filled 



with crystallized carbonate of lime 3 6 



e. Laminated sandy shales of a light blue colour, with a few bands 



of hard grit 1 3 



/. Bed of hard blue calcareous grit 2 



g. Bed of hard blue ferruginous shale indurated in some places. . . 2 6 



At this point an intrusive sheet of coarse dolerite, about 6 feet in 



