222 Heviews — Professor R, D. Salisbur//'s Physiography. 



The pit has yielded many rare fossils ; for instance, two specimens 

 of Faijolia, ten of Palmoxyris, ten of Eurypterus^ eight or nine of a new 

 shrimp-like animal, fourteen of Belmurus and Prestwichia, and one of 

 a true insect. But these have been collected (except in the case of 

 the shrimp-like animal, which has been found mostly during the last 

 year) during a space of time extending over the last five years, and in 

 the proportion of one rare animal to several thousand stones examined. 

 From the ninety nodules split by freezing were obtained — 

 18-20 uoudescript plaut-remaius, 6 ferns, 



1 root-filameut, 1 Unio, 



17 Annularia and Calamocladus, 3 Belitmrus 



1 Sphc)i02)h)/Ut(in, 1 Pahtoxiiris, 



3 LepidopltijUum, 1 ? Arthroplnira, 



1 Calaiuite, 2 shrimp-like animals, 



the remainder splitting badly or containing unidentifiable remains. 

 Of the naturally split stones found in the clay-pit, the commonest 

 organisms would certainly be the ferns ; second would come the 

 nondescript plant-remains, that is, a jumble of stems, fern-leaves, etc. ; 

 third, Calamocladus, etc. ; and fourth, Calamites. 



Of course, the extraordinary jjroportion of rare fossils may be due to 

 chance, or, more possibly, to that factor combined with an instinctive 

 collection of such nodules as are likely to contain good specimens. 

 To this instinctive selection may be attributed, to a great extent, the 

 undue preponderance of Calamocladus, etc. ; as these plants are 

 usually, in this pit at any rate, contained in small symmetrical oval 

 nodules, which would be more likely to be brought home than rough 

 irregular ones. But it is conceivable that those fossils, like fern 

 fronds or stems, which have a fairly broad surface and a layer of coaly 

 material more pervious to water than the stony matrix, would be 

 easily cracked by the recurrent frosts of Winter ; and that those of an 

 animal nature which have a chitinous covering more durable than the 

 stone, or at any rate have no coaly film to let the water into the plane 

 of the fossil, and those plant-remains that do not show a large flat 

 surface inside the stone, would be the ones that would resist longest 

 the natural disintegrating agencies. Hence it is possible that those 

 nodules which resist the longest may be just those which it would be 

 most worth while to persevere in cracking ; and in this way the 

 poverty of the faunal record in most coalfields may prove to be more 

 apparent than real. 



K, E ^^T I E] -V/- S. 



I. — Physiography. By Eollin D. Salisbuky, Professor of Geology 

 and Head of the Department of Geography in the University of 

 Chicago. 8vo ; pp. v + 770, with 24 plates and 707 text-figures. 

 London : J. Murray, 1907. Price 21«. net. 



PHYSIOGRAPHY owes much to the enthusiasm and industry of 

 its exponents in North America, of which the big volume before 

 us is one more token. The science has ill-defined borders which can 

 be to some extent rearranged at will to suit the scope of its demon- 

 strator. But although so eminent a geologist, Professor Salisbury 



