76 R. B. Oldham — Essays in Theoretical Geology. 



II. Coterminous with this there should be an area where deposition. 

 and subsidence are simultaneously taking place. 



III. The area of deposition and subsidence should gradually spread 

 outwards from the mountain range. 



IV. The region of denudation and elevation should gradually 

 encroach on that of deposition and subsidence. 



V. The demarcation between the areas of elevation and of subsi- 

 dence should be abrupt. 



VI. Near the limit the submontane deposits should, during 

 the elevation of the range, be raised with the accompaniment of 

 disturbance. 



VII. It is improbable that the system of disturbance would com- 

 mence simultaneously along its whole length, but rather it would 

 extend longitudinally as well as laterally. 



It is only necessary to compare this statement of the deductions 

 arrived at theoretically with the results of observation as given in 

 the first part of the paper, to see how close and complete is their 

 accordance. And in this agreement we find very strong evidence 

 of the truth of the theory. 



I have avoided overburdening the text with references ; none of the facts are here 

 published for the first time, and but little of the deductions. The ideas and con- 

 clusions relative to the history of the Himalayas are well known to those who have 

 worked at it ; in a more or less complete form they have been published at different 

 times, but have never before been collected together. The following papers have 

 been made use of, and should be consulted for further details : — 



Sir P. T. Uautley. On the Structure of the Sewalik Hills and the Organic 

 Eemains found in them. GeoL Trans, second series, vol. v. pp. 267-278 (1840). 



H B. Medlicntt. On the Geological Structure and Relations of the Southern 

 Portions of the Himalayan Ranges between the Rivers Ganges and Ravee. Mem. 

 Geol. Surv. Ind. vol. iii. part 2 (1863). 



F. Stoliczka. Summary of Geological Observations during a Visit to the Provinces 

 of Rupshu, Karnag, South Ladak, Zanskar, Suroo, and Dras of "Western Tibet, in 

 1865. Mem. Geol. Surv. Ind. vol. v. pp. 337-354 (1866). 



A. B. Wynne. Observations on some Features in the Physical Geology of the 

 Outer Himalayan Region of the Upper Punjab. Quart. Journ. Geol. Soc. vol. xxx. 

 pp. 61-80 (1874). 



H B. Medlieott. Note on the Sub-Himalayan Series in the Jamu (Jummoo) 

 Hills. Rec. Geol. Surv. Ind. vol. ix. pp. 49-57 (1876). 



A. B. Wi/nne. Note on the Tertiary Zone and Underlying Rocks in the North- 

 Western Punjab. Rec. Geol. Surv. Ind. vol. x. pp. 107-132 (1877). 



JNotes on the Physical Geology of the Punjab. Quart. Journ. Geol. 



Soc. vol. xxxiv. pp. 347-376 (1878). 



E. B. Medlieott. Manual of the Geology of India. Cap. 22, 23, 25, 26, 27 (1879). 



W. Theobald. The Siwalik Group in the Sub-Himalayan Region. Rec. Geol. 

 Surv. Ind. vol. xiv. pp. 66-175 (1881). 



H. B. Medlieott. The Nahan- Siwalik Unconformity in the N. "W. Himalayas. 

 Rec. Geol. Surv. Ind. vol. xiv. pp. 169-174 (1881). 



R. Lydekker. Geology of the Kashmir and Chamba Territories, and the British 

 District of Khagan. Mem. Geol. Surv. Ind. vol. xxii. (1883). 



R. B. Oldham. Note on the Geology of the Gangasulan Pargana of British 

 Garhwal. Rec. Geol. Surv. Ind. vol. xvii. pp. 161-167 (1884). 



Memorandum on the Probability of Obtaining Water by Means of 



Artesian Wells in the Plains of Upper India. Rec. Geol. Surv. Ind. vol. xviii. 

 pp. 110-112 (1885). 



C. S. Middlemiss. Physical Geology of the Sub-Himalaya of Garhwal and 

 Kumaun. Mem. Geol. Surv. Ind. vol. xxiv. part 2 (1890). 



