RAMBLES OF A GEOLOGIST. 429 



to about one-fifth the creature's entire length, and in the 

 Osteolepis and Diplopterus, to nearly one-seventh its length ; 

 while the length of the Glyptolepis leptopterus, a fish of the 

 same family as the Asterolepis, was about five and a half 

 times that of its occipital shield. If the Asterolepis was 

 formed in the proportions of the Diplopterus, the ancient in- 

 dividual to which this nail-like bone belonged must have 

 been about eight feet two inches in length ; but if moulded, 

 as it more probably was, in the proportions of the Glyptole- 

 pis, only six feet five inches. All the Coelacanths, however, 

 were exceedingly massive in proportion to their length : they 

 were fish built in the square, muscular, thick-set, Dirk-Hat- 

 terick and Balfour-of-Burley style ; and of the Russian spe- 

 cimens, some of the larger bones must have belonged to in- 

 dividuals of from twice to thrice the length of the Stromness 

 one. 



Passing upwards along the strata, step by step, as along a 

 fallen stair, each stratum presenting a nearly perpendicular 

 front, but losing, in the downward slant of the tread, as a 

 carpenter would say, the height attained in the rise, I came, 

 about a quarter of a mile farther to the west, and several 

 hundred feet higher in the formation, upon a fissile dark- 

 coloured bed, largely charged with ichthyolites. The fish I 

 found ranged in three layers, the lower layer consisting 

 almost exclusively of Dipterians, chiefly Osteolepides ; the 

 middle layer, of Acanthodians, of the genera Cheiracanthus 

 and Diplacanthus ; and the upper layer, of Cephalaspides, 

 mostly of one species, the Coccosteus dedpiens. I found ex- 

 actly the same arrangement in a bed considerably higher in 

 the system, which occurs a full mile farther on, the Dipte- 

 rians at the bottom, the Acanthodians in the middle, and 

 the Cephalaspides atop ; and was informed by Mr William 

 Watt, a competent authority in the case, that the arrange- 

 ment is comparatively a common one in the quarries of Ork- 



