A SUMMER RAMBLE AMONG THE HEBRIDES. 205 



ganic contents. The numerous bones disseminated through- 

 out the mass do not exist, as in so many of the Upper Old 

 Red Sandstone rocks, as mere films or impressions, but in their 

 original forms, retaining bulk as well as surface : they are 

 true grave-yard bones, which may be detached entire from the 

 inclosing mass, and of which, were we sufficiently well ac- 

 quainted with the anatomy of the long-perished races to which 

 they belonged, entire skeletons might be reconstructed. I 

 succeeded in disinterring, during my short stay, an occipital 

 plate of great beauty, fretted on its outer surface by numerous 

 tubercles, confluent on its anterior part, and surrounded on 

 its posterior portion, where they stand detached, by punctu- 

 lated markings. I found also a fine scale of Holoptychius 

 Nobilissimus, and a small tooth, bent somewhat like a nail 

 that had been drawn out of its place by two opposite wrenches, 

 and from the internal structure of which Professor Owen has 

 bestowed on the animal to which it belonged the generic name 

 Dendrodus. I have ascertained, however, through the in.- 

 dispensable assistance of Mr George Sanderson, that the genus 

 Holoptychius of Agassiz, named from a peculiarity in the 

 sculpture of the scale, is the identical genus Dendrodus of 

 Professor Owen, named from a peculiarity in the structure 

 of the teeth. Those teeth of the genus Holoptychius, whether 

 of the Lower or Upper Old Red, that belong to the second 

 or reptile row with which the creature's jaws were furnished, 

 present in the cross section the appearance of numerous 

 branches, like those of trees, radiating from a centre like 

 spokes from the nave of a wheel ; and their arborescent as- 

 pect suggested to the Professor the name Dendrodus. It seems 

 truly wonderful, when one but considers it, to what minute 

 and obscure ramifications the variety of pattern, specific and 

 generic, which nature so loves to preserve, is found to descend. 

 We see great diversity of mode and style in the architecture 

 of a city built of brick ; but while the houses are different, 



