A. The orientation of striae in eastern South America indicates that glaicers moved onto the continent from what is now the Atlantic Ocean (striae are scratches on bedrock made by rocks frozen into glacier bottoms as they pass over a surface). The world's oceans from a single system, and transport of heat from tropical areas guarantees that no major part of the open ocean can freeze.
B. African glaciers covered what are now tropical areas.
C. Indian glaciers must have grown in semitropical regions of the Northern hemisphere; moreover, their striae indicate a source in tropical waters of the Indian Ocean.
D. There were no claciers on any of the northern continents. If the earth got cold enough to freeze tropical Africa, why were there no glaciers in northern Canada or Siberia?
All these difficulties evaporate if the southern continents (including India) were joined together during this glacial period, and located farther south, covering the South Pole; the South American glaciers moved from Africa, not an open ocean; "tropical" Africa and "semitripical" India were near the South Pole; the North Pole lay in the middle of a major ocean, and glaciers could not develop in the Northern Hemisphere. Sounds good for drift; indeed, no one doubts it today.
II. The distribution of Cambrian triobites (fossil arthropods living 500 to 600 million years ago). The Cambrian trilbites of Europe and North America divided themselves into two rather different faunas with the following peculian distribution on modern maps. "Atlantic" province trilobites lived all over Europe and in a few very local areas on the far eastern border of North America--eastern (but not western) Newfoundland and southeastern Massachusetts, for example. "Pacific" province trilobites lived all over America and in a few local areas on the extreme western coast of Europe--northern Scotland and northwestern Norway, for example. It is devilisly difficult to make any sense of this distribution if the two continents always stood 3,000 miles apart.
But continental drift suggests a striking resolution. In Cambrian times, Europe and North America were separated; Atlantic trilobites lived in waters around Europe; Pacific trilobites in waters around America. The continents (now including sediments with entombed trilobites) then drifted toward each other and finally joined together. Later, they split again, but not precisely along the line of their previous junction. Scattered bits of ancient Europe, carrying Atlantic trilobites, remained at the easternmost border of North America, while a few pieces of old North America stuck to the westernmost edge of Europe.
{This must have been written by Steven Jay Gould- but I don't know where.}