The same may be said for Europe. De Quatrefages and many other students of the subject consider that the evidence is sufficient to establish the presence of man near the Atlantic coast in the Pliocene Epoch; and excellent English geologists have claimed that the caves in the valley of the River Clwyd, in north Wales, whose floors contain flint implements, had their entrance blocked by true glacial deposits, so that man was there present before the Great Ice Age began. From this brief presentation of the geologic evidence, the conclusion seems forced upon us that the ancestors of the American race could have come from no other quarter than western Europe, or that portion of Eurafrica which in my lectures on general ethnography I have described as the most probable location of the birth-place of the species.[30] _Scheme of the Age of Man in America._ -------------+-------------------+---------------------+----------------- AGE. | PERIOD. | GEOLOGICAL | HUMAN RELICS. | | CHARACTERS. | -------------+-------------------+---------------------+----------------- | {|Auriferous gravels of|Calaveras {|1. Pre-glacial. {| California (?). | skull (?). {| {|Lower lake beds in | {| {| Great Basin. | {| | | {| {|Attenuated drift. |Palæoliths from {| {|Columbia formation. | Claymont, Del. {| {|Sinking of Atlantic | {|2. First glacial. {| Coast. | {| {|Old glacial drift in | {| {| Mississippi Valley.| {| {|Brick clays. | {| | | {| {|Modified drift of |Flint chips {| {| Minnesota | and rude {| {|Medial Gravels in | implements. {|3. Inter-glacial. {| Great Basin. | {| {|Pampas formation. |Bone and stone {| {|New glacial drift and| implements. Quaternary {| {| till. fiords. | {| | | or {| {| | {| {|Moraines of Ohio |Palæolithic Pleistocene.{| {| Valley. | implements {|4. Second glacial.{|Loess of central | from the {| {| United States. | moraines. {| {|British America and | {| {| N. Atlantic |