140 
THE GEOLOGIST. 
position, &c., of the fish figured are as nearly as may be those of the 
specimen from which it is copied, other specimens show a considerably 
stouter body. The scales are of course restored, only small patches 
of these being preserved on any of the specimens. The dotted Hnes 
meant to show the probable size of the caudal and dorsal fins, unless, 
indeed, that fignired as a dorsal had really formed only part of the 
laro-e tail-fin. — I am, your obedient servant, Jas. Powrie, F.Q.S., 
Eeswalhe, Forfar. 
REMARKS ON MR. ROBERTS' PAPER ON CEPHALASPIS. 
Sir, — I venture to send you a few comments on Mr. George 
Roberts's paper on Cephalaspis in yom- last number. 
How your correspondent, Mr. G. E. Roberts, can talk (page 103) 
of the Lower Ludlow at Leintwardine being " clearly marked out as 
a littoral deposit'' by its " starfishes," after his paper in the " Geolo- 
gist" the other day announcing the discovery of starfish at one 
thousand two hundred and sixty fathoms depth, surprises me much. 
Equally does it surprise me (especially since his connexion with 
the Greological Society) to find him talking of the " Tilestone series 
passing into the underlying Silmian," when Sir R. Murchison, in 
his last edition of Siluria, has laid down (though, I confess, with a 
little confusion) that the beds between the Old Red and the Silurian 
are to be called Passage heels, and are quite different from his original 
Tilestones, which are clearly Upper Ludlow, being Downton Sand- 
stone. As long as this inattention to proper nomenclature is per- 
petuated, no one can understand what is written on the subject. 
The chief cause of error seems to lie in the end of the tenth 
chapter of Silm"ia, which appears to have been written before the 
present knowledge on the subject was obtained, and not corrected 
before sending it to press. The author there certainly speaks of the 
Tilestones and Passage beds of Kingston in connexion TVT.th Mr. 
Banks ; but those beds at Bradnor Hill are unquestionably Downton 
Sandstone. They were formerly by some called " Transition beds" 
(as marking the change to sandy from shaley beds), and were then 
considered to be equivalent to the Tilestones of Murchison, and which 
Tilestones were afterwards considered by some to be the same as the 
Passage beds, which, in fact, lie some distance above them. There 
is no excuse for the mistake on the part of my friend Roberts, who 
knows both, series of beds well, and I am sure can see no similarity 
between them. In fact (at page 106), he calls the King-ton beds 
Downton, but oddly enough distinguishes between the Downton beds 
and the Upper Ludlow, of which they are the top. In the same 
page (at top) he speaks of Cephalaspids being " abundant in the 
neutral ground between the Downton and' the Tilestones," which 
