114 Chronicles of Science. [Jan., 



being extensively employed in the construction of buildings of 

 various kinds with most satisfactory and economical results. The 

 preparation of concrete is treated very fully by Mr. Eeid, who de- 

 votes distinct chapters to lime concretes, concretes with compound 

 matrices, Roman cement concretes, and concretes made with Port- 

 land cement. He also gives descriptions of machinery for mixing 

 concretes and mortars, as well as remarks on building by frames. 

 In conclusion, some general observations of considerable value are 

 given on the advantages possessed by Portland cement as a building 

 material, in the course of which he mentions the success which has 

 resulted from the use of such concrete as a material for pavements. 

 Altogether this is a very useful work, which may beneficially be 

 consulted by all classes interested in the use of concrete. 



7. GEOLOGY AND PALAEONTOLOGY. 



(Including the Proceedings of the Geological Society, and Notices 

 of Recent Geological Works.) 



Memoirs of the Geological Survey. — Two of these Memoirs, form- 

 ing an important contribution to British Geology, have reached us 

 during the past quarter. One is a very elaborate ' Essay on the 

 Triassic and Permian Bocks of the Midland Counties of England,' 

 by Edward Hull, M.A., F.R.S., &c. (now Director of the Geolo- 

 gical Survey of Ireland). No less than twenty sheets of the 

 'Geological Survey' (one-inch) maps are referred to in this Memoir, 

 which include parts of the counties of Gloucester, Hereford, Wor- 

 cester, Warwick, Leicester, Stafford, Salop, Denbigh, Flint, Cheshire, 

 Derby, Notts, York, and Lancaster. The rocks are treated in 

 ascending order, under the following headings, or general classifica- 

 tion : — 



A 1. Rhsetic, or Penarth Beds. 

 A 2. New Red Marl (Keuper). 

 A 3. Lower Keuper Sandstone (Letten Kohle?). 

 Triassic Series .. [ (B. Muschelkalk, wanting in England). 

 C 1. Upper Mottled Sandstone 1 

 C 2. Pebble Beds \ (Bunter Sandstein). 



. C 3. Lower Mottled Sandstone ) 



Permian Series i lm U PP er Permian (Zecbstein). 



" \ 2. Lower Permian (Eothe-todte-liegende). 



The Lower Permian series may be arranged under two distinct 

 types of strata, called respectively the " Salopian " and the " Lan- 

 cashire," which differ lithologically, and were deposited in separate 

 hydrographical basins, the disconnecting barrier having been pro- 

 duced by the upheaval of the Lower Carboniferous rocks along a 

 tract of country crossing from east to west below the central plain 

 of Cheshire. Our readers will remember Mr. Hull's paper, recently 



