Reviews — Brief Notices. 379 



defended themselves from their carnivorous enemies by digging into 

 the ground". 



In a second paper Dr. Broom describes a species of Tylosaurus 

 (a Pytbonomorph) from the Upper Cretaceous beds of Pondoland ; in 

 a third paper he gives an account of a new type of Cynodont from the 

 Stormberg named Tritheledon riconoi, while the new family is called 

 the Tritheledontidse ; and in a fourth paper he discusses some points 

 in the Dicynodont skull. 



4. Pleistocene Geology of New York State. — This formed the 

 subject of the annual address to the Geological Society of America, 

 Mr. Herman L. Pairchild, President (Bull. Geol. Soc. Am., xxiv, 

 1913). The author discusses the limits, thickness, movement, and 

 recession of the ice, its erosional and constructional work together 

 with that of glacial waters in connexion with druralins, moraines, 

 eskers (sub-glacial), kames (extra-glacial), and other features. In 

 conclusion he refers to Glacial time, remarking that "the estimates 

 of those best qualified to judge of the length of Pleistocene time are 

 from 500,000 to 1,500,000 years". 



5. North American Camels. — After six years excavation at 

 La Brea, California, the University of California has been so fortunate 

 as to obtain several nearly perfect skulls of Camelops hesternus, and 

 varieties with associated skeletal material representing the greater 

 part of the animal. This has enabled Dr. Merriam to revise all 

 previous work on tlie group and speak with more certainty as to the 

 many species raised on imperfect material. (Univ. Calif. Publ., Bull. 

 Dept. Geol., vii (14), pp. 305-23, May, 1913.) 



6. The Mancts op Tbachodon. — A well-preserved skeleton of 

 Trachodon marginatus, Lambe, from the Edmonton formation of the 

 Red Deer River, Alberta, Canada, has allowed Mr. L. M. Lambe to 

 describe the manus in detail. This differs materially from the 

 description given by Barnum Brown of the manus of a specimen from 

 the Lance formation of Wyoming in 1912. That species was called 

 T. annectens. About four feet of the tuberculated skin is preserved 

 in the new specimen. Mr. Lambe gives a full account of the manus 

 and three plates in the Ottatva Naturalist, May, 1913. 



7. Road-metal. — The following paragraph is reprinted from reports 

 for the year 1912, on the Geological Survey, the Geological Museum 

 in Jermyn Street, etc. (P.P., Cd. 6793), 1913 : What is essentially 

 a new departure in the work of the Geological Survey of Scotland 

 was made in 1912. The Argyllshire County Council, recognizing the 

 importance of utilizing to the best advantage the great variety of 

 stones suitable for road-metal in that county, desired to purchase 

 a series of road-stone maps showing the occurrence of road-stones in 

 places easily accessible from the main roads. Maps were prepared on 

 the scale of six inches to one mile, on which were marked only the 

 outcrops likely to be of importance for this purpose. The surveyors 

 find them of great use, as the published one-inch maps are on too 

 small a scale to show all the smaller intrusions of igneous rock, some 

 of which make excellent road-stones. As they are not complete maps 

 they are comparatively inexpensive to prepare. 



