﻿Prof. Mantovaiii — Is Man Tertiary ? 435 



by superposed beds of volcanic tuif, the last and most extensive 

 marine deposit of that period in the Roman country. This volcanic 

 tuff was ejected from the volcano of Sabatini, actually represented 

 by the group of mountains which now form the basin of Lake Brac- 

 ciano. The Pleistocene strata are for the most part of mechanical 

 origin, and in a less degree of a chemical nature. They result from 

 the superposition of irregular beds of gravel, sand, and freshwater 

 marl, containing pebbles of various sizes, derived from the detritus 

 brought down from the Apennines. Limestone and poUerome silex 

 are most abundant, but a great quantity of broken crystals of 

 volcanic minerals, as augite, leucite, olivine, etc., are mixed with and 

 compose the gravel and sand. 



This volcanic debris has been derived from the decomposition and 

 erosion of the tuffs, or from the Latial Volcanos, whose eruptions 

 were contemporaneous with the formation of the valley of the Tiber. 



The chemical deposits are only seen in the broader expanses of 

 the valley, and result in the deposition of vast beds of travertin, a 

 freshwater limestone of very uniform texture, and largely used in 

 ancient and modern buildings. 



The earliest traces of primitive man consist of angular fragments 

 of silex evidently artificially worked. This silex is usually met 

 with in the form of flint-flakes or knives, spear or arrow-heads, and 

 celts or hatchets. These weapons are always chipped out roughly, 

 their surfaces are never smoothed or polished, consequently they are 

 referable to the Palteolithic or ArchEeolithic era of prehistoric man. 



In the same river-valley gravel, commingled with the worked 

 flints, are frequently found the bones of fossil Mammalia ; of 

 these relics of the extinct fauna of the Eoman country, the most 

 abundant are : 



Bos primigenius, Boj. 

 Eleplias primigenius, Blum. 



meridionalis, Nesti. 



antiquus, Falc. 



Others less common are : 



Sycena spelma, Goldf. 

 Castor Europ(Bu<i, Owen. 

 Ursus spelceus, Blum. 



Cervus elaphiis, Linn. 

 Hippopotamus major, Nesti. 

 Rhinoceros tichorhinus, Cuv. 

 Sus scrofa, Linn. 



Cervus {dana) Eomana, Ponzi. 

 Bos latifrons, Cus. 



The latest researches of this kind have disclosed a fact of the 

 highest importance, namely, that flint implements have been dis- 

 covered in the gravel forming the upper portion of the Pliocene 

 deposits (see Diagram, Bed C). I have collected some of these 

 flint implements myself on the Pliocene hills of Janiculus and 

 the Vatican ; but I must sincerely confess that the evidence of their 

 having been artificially formed appears to me to be open to doubt. 

 On the contrary, however, the flint implements of the alluvial deposits 

 leave no doubt as to their having been artificially formed by the 

 hand of man. For the jjresent therefore we will only consider 

 these undoubted traces of man contemporaneous with the great 

 Mammalia in the Quaternary deposits. 



The first and most evident conclusion that may be drawn is, that 



