HISTORY OF SOUTHEAST MISSOURI 223 5 to 30 feet in depth. Lyell gives this account oi the cavities which he saw at Xew Madrid : "Hearing that some of these cavities still existed near the town, I went to see one of them, three-quarters of a mile to the west- ward. There I found a nearly circular hol- low, 10 yards wide and 5 feet deep, with a smaller one near it, and I observed, scattered about over the surrounding level ground, fragments of black bitiuninous shale, with much white sand. Within a distance of a few hundred yards were five more of these sand- bursts, or sand blows, as they are sometimes termed here, and rather more than a mile farther west, near the house of Mr. Savors, my guide pointed out to me what he called 'the sink hole where the negi'o was drowned.' It is a striking object, interrupting the regu- larity of a flat plain, the sides very steep and 28 feet deep from the top to the water's edge. The water now standing in the bottom is said to have been originally verj^ deep, but has grown shallow by the washing in of sand and the crumbling of the bank caused by the feet of cattle coming to drink. I was assured that many wagon loads of matter were cast up out of this hollow, and the cjuantity must have been considerable to account for the void; yet the pieces of lignite and the quantity of sand now heaped on the level plain near its borders would not suffice to fill one-tenth part of the cavity. Perhaps a part of the ejected substance may have been swallowed up again and the rest may have been so mixed with water as to have spread like a fluid over the soil." Bringier says: "The whole surface of the country remained covered with holes which, to compare small things with gi'eat, resembled so many craters of volcanoes surrounded with a ring of carbonized wood and sand, which rose to the height of about seven feet. I had occasion a few months after to sound the depth of several of these holes and found them not to exceed 20 feet ; but I must remark the quicksand had washed into them." Perhaps the most noticeable of these sinks still to be found in the earthquake region are along the west side of the Little river bottoms. Just east of the town of Caruth in Diuiklin eoimty there are a number of these sinks well defiaied in portions and still known to the inhabitants as having been caused by the earthquake shocks. They exist, of course, in other parts of the section, but are not numer- ous. It is difficult to determine exactly how they were cavised, but in all probability were the result of the forcing out of large quanti- ties of sand through the cracks in the allu- vium, or through the sinking away of the sand at the bottom into the nearby bed of some stream. It must be remembered that the sand was in a semi-fluid condition and would easily flow away through a crack opened in the bank of a stream. Various conjectures as to the cause of these shocks have been suggested. A few persons at the time advanced the idea that they were caused by volcanic action. This idea was rejected, however, by those acquainted with the country, owing to the absence of any indi- cation of volcanic action. Another opinion was that they were due to disturbances in the moiuitains to the west. Some have thought the earthquakes were caused by some change taking place in the alluvial soil itself; they have suggested the caving of the banks of the river, the filling in of imderground caverns, the explosion of masses of gas and oil. The quotation of Nut- tall in another place refers to the earthquake
