In the middle 1800s a man by the name of Albrecht Koch began excavating for mastodon remains in the southern part of Benton County, Missouri. In the middle 1840s this would be the northern part of Hickory County, which was formed from Benton and Polk counties in 1845. The excavation site was located about 8 miles north of where Wheatland is now and was near the Pomme de Terre River in Breshears Valley. This valley is said to have contained about 6000 acres of land and is very near Avery, which is on the Benton and Hickory County line. The valley is surrounded by hills.

Down through the years there have been discussions and differences of opinion on when the mastodon bones were excavated the first time. 1833, 1839 and 1844 have all been given as the time of the first dig. Most sources believe the 1839 time period is accurate. 1844 was most likely the date that one skeleton was shipped to the British Museum in England. Mr. Koch's given name has also been found as Albert in some sources.

Fossils were found in the valley in the 1830s, leading to speculation that prehistoric animals had at one time inhabited this valley. Perhaps Mr. Koch had some connection to residents of the area or he may have learned of this from Frenchman who were supposed to have come into the area in the late 1830s looking for buried silver. Judge James H. Lay of Warsaw in Benton County wrote a history of Benton County, Missouri and in his book he told of the search for the lost silver. Some years earlier a group of Frenchman were supposed to have been going down the river with bullion and coins. They were pursued by Indians and abandoned their boats at the mouth of the Pomme de Terre and buried the silver. In later years other Frenchman came into the area with information on the burial spot and were supposed to have located guns but no silver. Tales of buried treasure in the area are still around today. A buried treasure map was published a number of years ago and Hickory County, Missouri was shown as having a buried treasure. The place where the guns were found was later to become the Henry Breshears farm where the "Bone Hole" was located. The "Bone Hole" was a spring bog with water 3 inches deep year round and a spring at the edge. Some bones supposedly sank out of sight. This is where Mr. Koch found the many bones he excavated. He used wooden pipes made by local residents for the excavation. One skeleton was said to be 20,000 years old and 23 feet high. Mr. Koch set about to assemble the bones, but his Mastodon skeleton was not true to form, although he did draw large crowds on his tours with the skeleton. The discovery was in a museum in St Louis Missouri for a short time.

In 1844 the skeleton was shipped to the British Museum in England and was taken apart by specialists in that field and reassembled correctly. It is still a favorite display at the museum. The tusks of this skeleton are 9 feet in length. The purchase price for the skeleton is said to have been as much as $20,000.

After Mr. Koch's discovery a number of other hunters looked for bones, but he had excavated most of the bones that were considered worthwhile and the excitement faded away.