10 Account of the 



church of Jra Cceli, is ten feet higher. It is probable that, 

 when the Capitoline hill was selected as a proper situation for a 

 fortress, it was nearly inaccessible on all sides^ except on that 

 next the Forum. The crumbling of the rock of which it is 

 composed, and the accumulations of rubbish, have, in the lapse 

 of ages, rendered the sides less abrupt. 



Of all the hills of Rome, this affords the best opportunities of 

 discovering the internal structure, from the numerous excava- 

 tions that have been made in it, anciently and by the modern 

 Romans ; and all the mineral substances found in the other hills 

 are met with here. 



In some excavations at the foot of the Tarpeian rock, the 

 strata of marine formation are discovered, forming the subsoil 

 upon which the volcanic and all the other superincumbent ma- 

 terials have been deposited. They consist (in ascending or- 

 der) of, 



1. A bed of a dry semi-indurated brownish clay, with scales 

 of mica; slightly calcareous; thickness not discernible. 



2. Thin beds of compact limestone, interstratified with the 

 preceding clay. 



3. A bed, four feet thick, of grey sand, slightly agglutinated, 

 composed of grains of tufa, limestone, and a great deal of mica, 

 with a thin band of the compact limestone. 



4. A bed, two feet thick, of yellow clay. 



5. A bed, five feet thick, of granular tufa, of a blackish co- 

 lour, containing a distinct layer of limestone pebbles. 



6. Another bed of five feet in thickness, of a grey c^olour, of 

 granular tufa. 



7. Stony tufa, which continues to the summit of the Tarpeian 

 rock, and, therefore, about 100 feet in thickness. 



I'he bed of yellow clay, No. 4., is the uppermost of what may 

 strictly be termed the marine deposits. 



The northern part of the hill is also composed almost wholly 

 of the stony tufa. 



In the intervening space, the iniermontium, are found exten- 

 sive fresh water deposits, consisting of a recomposed granular 

 tufa and yellowish clay-marl, of two sorts ; the one indurated, 

 containing fragments of pumice, of the stony lava, vegetable re- 

 mains, and numerous lacustrine shells ; the other variety is of a 



