72 REVIEWS. 



lower, middle, and upper old red sandstone groups. Each of these groups 

 of rocks is characterized by special forms of fish remains, the upper and 

 lower most resembling each other, and differing widely from the fishes of 

 the middle group. It would appear, also, that the fish remains occur in 

 beds interstratified with others containing remains of plants, which have 

 never been thoroughly described, but on which a new light is thrown by 

 the fossil plants discovered by the Government surveyors at Kiltorcan, in 

 the County of Kilkenny, and by Mr. Griffith, at Tallow-bridge, in the 

 County of Waterford. We shall give our readers Mr. Miller's sketch of 

 each of these three formations, and add a few remarks to illustrate their 

 bearing upon the interesting questions relating to the Irish red and yellow 

 sandstone beds 



" Above the upper beds of the great conglomerate, at distances varying from 

 forty to a hundred and sixty feet, the fishes of the lower old red sandstone ap- 

 pear curious, as the most ancient ganoids known to the geologist, and further, from 

 the circumstance that, while the still older placoids of the upper silurian system 

 exist merely as detached teeth, spines, and shagreen points, these old red fishes 

 exhibit in the better specimens the entire outline of the original animals, with not a 

 few of their anatomical peculiarities. It is from this formation that our knowledge 

 of the oldest skulls, of the oldest vertebral columns, and of the oldest pelvic and 

 thoracic arches, anywhere preserved, is to be derived. With the fish we sometimes 

 find associated, though not often, specimens illustrative of what seems to be our most 

 ancient terrestrial flora club mosses reed-like casts and impressions, streaked 

 longitudinally, like the interior of the calamite, but apparently without joints what 

 appear to be ferns and, in at least one unique specimen, a true wood of the arau- 

 carian family the oldest which has yet presented its structure to the microscope." 



Of the middle red sandstone system, Mr. Miller observes 



" There is, perhaps, no Scottish formation in which the palaeontologist has still 

 so much to do as in this middle old red sandstone. Our respected President, Dr. 

 Fleming, called attention, a full quarter of a century ago, to some of its plants, and 

 again took up the subject no farther back than last year, in an interesting paper 

 read before our society ; and Agassiz has figured and described some of its fishes, 

 and, more particularly and incidentally, at least one of its crustaceans. But much 

 still remains to be done. From what I have seen of Mr. Webster's collection, I 

 should infer that materials have been already accumulated sufficient for the restora- 

 tion of its great crustacean one of the most gigantic of its family, whether recent 

 or extinct ; and as the Den of Balruddry has furnished, of itself, nearly a hundred 

 specimens of Cephalaspis (still a comparatively rare ichthyolite elsewhere), most 

 of which are now in the hands of Lord Kinnaird, it would be well that some ich- 

 thyologist had access to the collection, in order to determine whether in Scotland, 

 as in England, we have more than one species of this singular genus. Dr. Fleming 

 found in this middle old red formation an apparent fern, with kidney-shaped leaf- 

 lets ; and it yielded several years ago, near Clockbriggs, in Forfarshire, a large 

 specimen of Lepidodendron, which exhibits the internal structure. I owe a frag- 

 ment of this fossil to an intelligent geologist, Mr. William Miller, banker, Dundee; 

 but so imperfect is its state of preservation, that, though it presents to the micro- 

 scope the large irregularly-polygonal cells of its genus, it bears none of the nicer 

 specific marks which might serve to distinguish it from the several greatly more 

 modern species which occur in the coal measures." 



The occurrence of Lepidodendra so far down hi our geological scale as 

 the middle old red sandstone is an important fact, if it be well ascertained. 



