Bulletin - United States Geological Survey Volume 494 - Tapa blanda

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1912 Excerpt: ...absence of deltas indicates that the uplift or deformation occurred suddenly. Furthermore, it is found that while great cypresses, sycamores, and poplars, sometimes two or three centuries old, grow over the general surface of the dome, no trees older than 70 or 75 years grow within the unoccupied bayous; from which it may be inferred that the uplift occurred at least 70 or 75 years ago, and probably not much earlier. The amount of uplift, judging from the fact that the land is only 10 to 15 feet above high-water mark, could not have been over 15 or 20 feet. Some of the uplift was almost certainly due to the earthquake of 1811, but if Little Prairie, on which New Madrid is situated, is a part of the dome, the uplift will have to be referred to an earlier date, as New Madrid village previous to the shock was on high land, never covered by the floods. Blytheville dome.--This dome, which, as previously stated, is 7 to 10 miles in diameter, has the same general characteristics as the Tiptonville dome, just described, with the exception that its continuity is broken by valleys formed by the meanders of Pemiscot River and by indentations due to former swings of the Mississippi, the position of which is now marked by the bayous known as Clear and Flat lakes. The elevation, if actually a dome as there is good reason to believe, did not result from the shock of 1811, for the Mississippi, which has manifestly had a part in shaping its outline, has not flowed against it since that date. The widening of the Pemiscot Valley by the meandering of the stream is likewise an earlier feature, relatively little change having taken place since 1811. The total uplift is probably not over 10 or 15 feet. Little River dome.--Little River dome does not differ in general character fro...