240 
THE GEOLOGIST. 
The extreme abimdance of the homstone nodules in the palaeozoic lime- 
stones of America will render it easy to our Transatlantic contemporaries 
to multiply observations in this new field of research, which presents an 
interesting addition to the labours of the microscopist, while English geo- 
logists should at once examine the siliceous concretions which occur in our 
British rocks of older than cretaceous age. It will be remembered by 
those who undertake such examinations that the use of turpentine renders 
the chips of chert almost as transparent as glass. 
In ' Silliman's Journal' for May, Dr. White publishes descriptions with 
figures of some of the more frequently recurring forms hitherto observed 
by him ; some of which figures we copy here for the benefit of our readers, 
referring those who are specially interested in the subject to our first-class 
contemporary, the 'American Journal of Science,' for further details. 
EEYIEW. 
Monograpliie des G aster ojpodes et des CephaJopodes des Couches Creiacees 
Superieures du Limhourg. By M. Binkhorst. 
We recently noticed (page 79) an excellent Monograph by this geologist 
on the Gasteropoda of the Upper Chalk of Limbourg ; since then we are 
indebted to M. Binkhorst for a copy of his valuable Monograph of the 
Cephalopoda of the same geological beds, illustrated by six handsome 
quarto plates, containing ninety-one figures. The letter-press consists 
entirely of descriptions, lists of synonyms, and stratigraphical ranges of 
the following species, which are met with in that district : — Belemnitella 
mucronata, D'Orb. ; AcanthoteutJiis MaestricJdensis, n. s. ; Nautilus de- 
pressus, n. s. ; N. Seherti, n. s. ; N. Vaelsensis, n. s. ; N. Lehardii, n. s. ; 
N. Daniciis, Schlot. ; Rhyncholithus Deheyi, Miiller ; M. minimus, n. s. ; 
R. ? Ruchii, Miiller ; Ammonites pedernalis, Buch. ; A. colligatus, n. s. ; 
A. Decheni, n. s. ; A. exilis, n. s. ; A. j^uvgens, n. s. ; A. laticlavus?, 
Sharpe ; AptycTiiis rugosus, Sharpe ; Samites ro^wz c?w5, Sowerby ? ; S. 
cylindraceus, D'Orb. ; Scaphites constrictus, D'Orb. ; Baculites Faujasi, 
Lamarck ; JB. anceps, Lamarck ; B. carinatus, n. s. 
We are very glad to know that M. Binkhorst is busily preparing a 
Monograph of the bivalves of these interesting beds of Chalk, and that 
every day his researches are rewarded with new forms, not only of 
Conchifera but of Gasteropods. 
Within the last few w eeks he has added no less than thirty new species 
of the latter, to the number described in his Monograph, a hst of which 
was given in our February number. 
Bich as this Maestricht Chalk is in genera and species, we are satisfied 
that the " Chalk-rock " beds of our own Upper Cretaceous Series would 
as richly reward English collectors as we are glad to find these Maestricht 
beds are rewarding our indefatigable and talented Flemish contemporary. 
