EXPLANATION OF THE PLATES. 



thyosaurus : p. 117. a. shows the exterior and posterior extremity ; h. the bone 

 laterally, exhibiting the basilar process ; c. the upper and interior surface. 



Plate XXI. 



Figs. 1, 2, 3. Posterior extremity of a jaw, probably of Plesiosaurus ; belonging to 

 Colonel Birch: — described p. 122. 1, The superior surface; 2. outer side; 

 3. inner side. 



Figs. 4, 5, 6. Humerus of peculiar form, found with the preceding : p. 122. 



Plate XXII. 



Fig. 1. Femur of Plesiosaurus. Fig. 2. Os pubis. Fig. 3. Os ilium. All described 

 p. 122. 



Figs. 4 to 8. A series of vertebrae from the Kimmeridge clay ; found both near Wey- 

 mouth and at Heddington ; probably belonging to a new species of Plesiosau- 

 rus : see p. 123. 



PLATE XXIII. 



A Map of part of the course of the river Sutluj, in the Himalaya mountains ; in illus- 

 tration of Mr. Colebrooke's paper. Article X. p. 124. 



This map, as well as part of Plate XXIV, will serve also to illustrate 

 Mr. Fraser's Notes on the Himalaya Mountains, — Vol. V. p. 60. 



PLATE XXIV. 



Fig. I. A Map of part of India, in illustration of some of the papers published in the 

 Geological Transactions ; the routes or tracts of country referred to being de- 

 noted by different colours. 



1. Yellow, — denotes the tract described in Mr. Colebrooke's paper, Art. X. p. 124, 

 of the present volume ; showing the connexion of the valley of the Sutluj, repre- 

 sented on a larger scale in Plate XXIII, with the adjoining country. 



2. Brown. — Mr. Eraser's route from Delhi to Bombay, described in his paper, 

 Art. XII. p. 141. 



3. Green, — points out the parts of the N.E. of Bengal, referred to in Mr. Cole- 

 brooke's paper. Art. XI. p. 132 ; and in Mr. Scott's Letter, Art. XIII. p. 167, 

 of the present volume. 



4. Blue, — denotes the tract described in Dr. Adams's paper on the geology of the 

 banks of the Ganges, from Calcutta to Cawnpore, Vol. V, Art. XVII, p. 346. 



5. Red. — The Island of Salsette: — Mr. S. Babington's paper; Vol. V. p. 1. 



Fig. 2, — from a sketch by Mr. Eraser, illustrates the structure of the basaltic heights 

 described at p. 158 of Mr. Eraser's paper, Art. XII. of the present volume. 



