June 11, 1886.] 



SGIEJSTGE. 



535 



As an example of possible improvement, we may 

 take the charts showing the fluctuations in the 

 relative values of silver and gold. There are four 

 such charts scattered in various parts of the book, 

 without any apparent connecting-link. 



The work is altogether so suggestive, that those 

 who agree, as well as those who disagree, with the 

 author's views, will find ample food for thought in 

 reading it. The ground covered is so wide and 

 the treatment so uniform, that it is scarcely possi- 

 ble to select one passage for comment rather than 

 a score of others. It may be remarked, however, 

 that the author's views of the ethical question 

 involved in the monetary change of 1834 coincide 

 more nearly with those of the advocates of free 

 silver coinage at the present time, than we like 1 to 

 see. Up to 1834 our currency was on an almost 

 pure silver basis, as the value of the gold in the gold 

 dollar was a little greater than that of the silver 

 in a silver dollar. In order to bring gold into 

 circulation, it was necessary to change the ratio, 

 which might be done either by increasing the 

 weight of the silver dollar or diminishing that of 

 the gold dollar. The latter course was adopted, 

 on the ground, that, as silver was the standard at 

 the time, the new coinage of gold should be ac- 

 commodated to it. Professor Laughlin objects to 

 this, that in reality the change in the marked 

 ratio before 1834, which necessitated the new 

 ratio, consisted in a depreciation of the value of 

 silver ; and that in consequence it was the silver 

 dollar which should have been made heavier in 

 order to bring it up to the old standard. This is 

 the very argument on which the silver men now 

 sustain their views. They claim that gold has 

 appreciated in value, and that we should go back 

 to the old silver dollar, the value of which they 

 believe to have been more stable than that of the 

 gold dollar. In either case, we think the sound 

 view to be that the standard for the time being 

 should be accepted rather than that of some past 

 time. 



GEOLOGY OF ARABIA AND PALESTINE. 



In 1883 the committee of the Palestine explora- 

 tion fund wisely took advantage of an interruption 

 of its regular work caused by the interference of 

 the Turkish government to send Professor Hull, 

 with a well-selected party, to explore some of the 

 less-known districts of Arabia Petraea and south- 

 ern Palestine, — regions of interest not merely 

 geologically, but historically as well. 



The route of the party extended through the 

 Sinaitic peninsula, and thence into the Wady 



Physical geology and geography of Arabia Petraea, 

 Palestine, and adjoining districts. By Edward Hull. 

 Adelphi, Com. Palestine explor. fund, 1886. 4°. 



Arabah and to the southern end of the Dead Sea, 

 then over the Judean hills to Gaza, and from this 

 place to Joppa, Jerusalem, and the Jordan valley. 

 The intention to explore farther north was frus- 

 trated by the snow of an unusually severe winter. 

 The exploration was thus somewhat limited in 

 its range : but Professor Hull has supplemented 

 it by references to the works of the numerous 

 geologists who have at various tunes studied the 

 rocks of the districts traversed, and of the ad- 

 jacent regions around the eastern end of the 

 Mediterranean, which have many points in com- 

 mon. 



Geologically considered, the district in question 

 is part of an extensive region of western Asia and 

 northern Africa, characterized by the wide distri- 

 bution of cretaceous and eocene marine limestones 

 resting on old and for the most part crystalline 

 rocks, and in part overlaid and margined by very 

 recent deposits. 



The old gneisses and schists penetrated by great 

 dikes and masses of intrusive granite and diorite, 

 which constitute the mass of the Sinaitic Moun- 

 tains, and extend thence along the Gulf of Akabah 

 and the Wady Arabah, are similar in mineral char- 

 acters to the Laurentian rocks of this continent ; 

 and Hull agrees with Oscar Fraas and the writer 

 of this notice in referring them and similar rocks 

 of upper Egypt to that ancient system. Thus we 

 have the interesting fact that the nucleus of the 

 old historic lands of Egypt and Arabia is composed 

 of the same venerable rocks which occupy a simi- 

 lar place in northern Europe and in North Amer- 

 ica. Flanking these oldest rocks, there seem to 

 be in Arabia, as in Egypt, newer slates and schists 

 and igneous rocks, probably of Huronian or old 

 Cambrian date. 



Here, however, there occurs a great gap in the 

 sequence, and we find nothing to represent the 

 Siluro-Cambrian, Silurian, or Devonian systems ; 

 the next rocks in ascending order being sand- 

 stones, conglomerates, and limestones, the ' desert 

 sandstone' of our author, which hold carboniferous 

 fossils. These beds are not of great thickness or 

 horizontal extent, but afford unequivocal evidence 

 of their age in the fossils of the genera Zaphrentes, 

 Productus, Orthis, etc., which they have afforded. 

 A true lepidodendron has also been obtained from 

 the sandstone. 



Until recently these carboniferous rocks were 

 confounded with an overlying sandstone of some- 

 what similar character, but of much greater thick- 

 ness, — the Nubian sandstone, which is probably of 

 lower cretaceous age, though it is by no means 

 certain that it may not represent the Jurassic or 

 even the trias. The relations of these sandstones, 

 both in Arabia and Egypt, are somewhat perplex- 



