88 Reviews — Monazite Sand Deposits, Travancore. 



de noms desuets ou inconnus parfois de tons, Be peuvent que jeter 

 le trouble dans la nomenclature, et elles ne sont justifiees que 

 lorsque le nom usite a ete deja preemploye pour une autre forme." 



On similar grounds the genus Roudaireia, of Munier-Chalmas, 

 1881, is adopted instead of Stoliczka's Veniella of 1871, -which 

 undoubtedly has priority. It may be pointed out, likewise, that 

 the original orthography of Area esnaensis has been altered, without 

 comment, to A. esnehensis. We consider that the genus Ostrea, of 

 which many species are discussed, would have added much to its 

 distinctness if it had been divided up into the well-known genera of 

 Gryphma, Exogyra, Alectryonia, etc., although it may occasionally be 

 difficult to place a species through slight overlapping of its characters. 



The " Tableau Synoptique " furnishes a useful conclusion to this 

 monograph in which the forms are listed in the order of description, 

 together with their stratigraphical and geographical distribution. 

 Pour stages of the Upper Cretaceous are recognized, viz. Cenomanian, 

 Turonian, Emscherian, and Aturian, while the occurrences are 

 entered under Egypt, Sinai, and other countries. 



It is hoped that many more parts of this " Palaeontological Series" 

 may be issued by the Geological Survey of Egypt, although in future 

 memoirs we strongly recommend the addition of an alphabetical 

 index of all the species and genera, wherever mentioned in the text, 

 either as synonyms or otherwise. 



There should be a great demand for this volume and those 

 previously published, being indispensable to the student of 

 Egyptian palaeontology. 



XIII. — Report on the Monazite Sand Deposits in Tratancoee. 

 By I. C. Chacko, State Geologist, pp. 13. Trivandrum, 1917. 



rpHE monazite sand deposits of Southern India have now become of 

 X considerable commercial importance, and the Government of 

 Travancore has carried out a complete survey of all the known 

 deposits within its territory. The country rock is mainly composed 

 of charnockites and leptynites, overlain in places by the Warkalay 

 beds, which are supposed to be Tertiary and equivalent to the 

 Cuddalore sandstones of the east coast. The monazite is found in 

 the sands of the seashore, which are black in colour, owing to the 

 presence of much magnetite and ilmenite, together with garnet, 

 rutile, apatite, and zircon. The total area covered by sands rich 

 enough in monazite to be worked is estimated at 1,427 acres, 

 calculated to contain about 17,000,000 tons of monazite. However, 

 owing to tides, currents, storms, and floods, the total amount of sand 

 seems to vary considerably from time to time. Some of the sand- 

 dunes near the shore are also rich in monazite. The monazite is 

 undoubtedly derived from the charnockite series : certain pegmatites 

 are specially rich in this mineral, but it is probably widely dis- 

 seminated in small quantity. It is believed that it has mainly 

 passed from the old rocks to the coast deposits by way of the 

 Warkalay beds and has been concentrated in the modern sands by 

 the action of rivers and the waves of the sea. It is possible that 



