Questions 31-44 are based on the following passage.
Uncovered at Johnson's Shut-Ins
In Reynolds County, Missouri, a one-billion-gallon blast of Q31 water caused by a breach of the Taum Sauk reservoir roared down Proffit Mountain into the east fork of the Black River on December 14, 2005. Q32 They ripped a channel through Johnson's Shut-Ins, one of Missouri's most popular state parks. Though flood damage marred the Q33 parks beauty for a time, the scar the raging water left in its wake Q34 specifically revealed over a billion years' worth of Earth's geologic history.
The area known today as Johnson's Shut-Ins State Park Q35 bad began to develop 1.5 billion years Q36 ago. When the volcanoes that created the St. Francois Mountains exploded. Slow-moving magma Q37 cooled down its temperature and crystallized to Q38 form silica-rich rhyolite rock. Over time sedimentary rock such as limestone and shale, formed from material deposited by shallow inland seas, buried the rhyolite. After the seas had receded, gravel-rich rivers and streams eventually chipped away the soft sedimentary rock in some areas, exposing the erosion-resistant rhyolite rock and creating pockets and pits. In low places, the Black River was confined Q39 (or "shut in") by the Q40 rhyolite and creating the natural waterslides and canyon-like gorges that have become a summer playground for thousands of visitors.
Although the flood left the shut-ins unscathed, the surge of water that tore through the park in 2005 stripped away all trees, soil, and sedimentary rock Q41 in its path. Left behind is a channel that is composed of granite-and previously unexposed rhyolite rock-and Q42 contain rocks from at least three other geological eras. The menacing floodwaters also revealed a half-billion-year-old beach made of both sand and gravel.
Five years of work has restored most of the park surrounding the shut-ins. Q43 Some have returned Q44 back. Geologists from around the world visit to get a close look at the ancient volcanic rock along what has been named the "Scour Channel." The "Scour Channel" now rivals the park's other geologic curiosities for most frequently visited site.