370 Reviews — P. Choffat, the Jura of Portugal. 



observations indicate that the profundities of the sea are much less 

 than those given by actual soundings. In short, theory and practice 

 are, as usual, at variance ; and, of course, Mr. Milne holds that in 

 this case practice is at fault. Sooth to say, his proposition (that, in 

 deep sea soundings, owing to the continuous running out of the line, 

 after the lead has touched the bottom, it is very hard to determine 

 the depth with accuracy) seems sound enough. He concludes his 

 contribution with a paragraph on the importance of systematic tide 

 observations in Japan, which he holds, if properly made and 

 recorded, would be of great service not only to the hydrographer 

 and navigator, but also to the physicist and geologist. 



III. — Etude Stratigraphique et Paleontologiqtje des Terrains 

 JuRASSiQUES DU PORTUGAL. Par Paul Choffat. Premiere 

 livraison : Le Trias et le Dogger au Nord du Tage. 4to. 

 pp. 72, with local sections. (Lisbon, 1880.) 



THE subject of Portugal cannot fail to be of interest to the fellow- 

 countrymen of Daniel Sharps, whose researches, published in 

 the Proceedings of the Geological Society of London for 1839, and 

 in the Quarterly Journal for 1849, laid the foundations of its Meso- 

 zoic geology. The value of Sharpe's work is cordially acknowledged 

 by the author ; and, though M. Eibeiro, in a series of publications 

 dating from 1852, has found it necessary, whilst paying close at- 

 tention to the Jurassic series, to make material alterations, especially 

 in Sharpe's stratigraphy, his work must be always regarded as 

 something more than the flying visit of an amateur geologist. 



On comparing the zones of the Lias with those held to obtain in 

 the rest of Europe, the author notes the absence of the zone of Avicula 

 contorta, and probably of the zone of Am. planorbis : a different 

 development, or perhaps the absence of the whole of the base of the 

 Sinemurian : a partial and different development of the zones of 

 Am. Davcei and Am. Ibex : a different development of the Toarcian, 

 at least in the upper part, corresponding to the base of the Bajocian 

 of Oppel. He places the zones of Am. opaliniis and Am. MurcM- 

 sonm with the Toarcian, though suggesting that some day the whole 

 may be classed with the " Dogger," or Brown Jura. The absence of 

 the above zones is not due to gaps in the series, the sedimentation 

 appearing to have been continuous. 



For him the *' Dogger " commences with the zone of Am. Sowerhyi, 

 and comprises a good thickness of marly and white sub-oolitic lime- 

 stones, including the Bajocian, occasionally the Bathonian, and the 

 " Calloviau." Throughout the whole of this series corals are rare. 

 The principal fossils are Cephalopods, Brachiopods, and Echino- 

 derms. Lamellibranchs are moderately plentiful, whilst the lists 

 show few Gasteropods. 



The most noteworthy circumstance is that where the Bathonian is 

 absent, it is replaced by the Callovian, which comprises much more 

 than the mere equivalents of the Kelloway rock, incUiding in fact 

 what we should call the Cornbrash, and a large portion of Oxford 

 Clay. The characteristic Ammonites are there, with the exception 



