Covering a vast extent of the southern portion of Russia in Europe, occurs the sandy clay which is commonly known as Loess, whose origin has given rise to the most varied and conflicting opinions. In the course of a visit to the above country, this deposit struck the writer as well worthy of further study, whilst its connection with the Black Earth invited closer inspection. Its distribution and general characters, as regards the greater part of Western and Central Europe, have been dealt with in a most masterly manner by Baron von Richthofen in his “China,” chap. v.; but at the Russian frontier his description ceases almost abruptly, and he merely mentions that the Dniester and its tributaries appear to have cut their channels through the Loess.