 Sarnia is located on the eastern shore of Lake Huron at its extreme southern point where it flows into the St. Clair River . Most of the surrounding area is flat , and the elevation ranges from 169 metres ( 554 ft ) and 281 metres ( 922 ft ) above sea level . The soil mostly comprises clay . Despite this high percentage of clay , the soil is remarkably rich for cultivation . Prior to the Ice Age , glaciers covered most of the area , as can be seen not only by the existence of the Great Lakes themselves but also of alluvial sand deposits , terminal moraines , and rich oil reserves . The entire area was submerged and plant and animal matter formed many layers of sediment as they settled after the waters receded . Sarnia is not part of the Canadian Shield and is located just beyond its southernmost reaches , 290 kilometres ( 180 mi ) West of Toronto and 106 kilometres ( 66 mi ) North of Detroit . 
 Sarnia is located on the eastern shore of Lake Huron at its extreme southern point where it <a href='uninflect' title='1'><mark>flows</mark></a> into the St. Clair River . Most of the surrounding area <a href='drop_aux' title='2'><mark>is</mark></a>flat , and the elevation <a href='uninflect' title='3'><mark>ranges</mark></a> from 169 metres ( 554 ft ) and 281 metres ( 922 ft ) above sea level . The soil mostly <a href='uninflect' title='4'><mark>comprises</mark></a> clay . Despite this high percentage of clay , the soil <a href='drop_aux' title='5'><mark>is</mark></a>remarkably rich for cultivation . Prior to the Ice Age , glaciers covered most of the area , as can be seen not only by the existence of the Great Lakes themselves but also of alluvial sand deposits , terminal moraines , and rich oil reserves . The entire area was submerged and plant and animal matter formed many layers of sediment as they settled after the waters receded . Sarnia <a href='negative_concord' title='6'><mark>is</mark></a> <a href='negative_concord' title='7'><mark>not</mark></a><a href='negative_concord' title='8'><mark>part</mark></a> of the Canadian Shield and is located just beyond its southernmost <a href='uninflect' title='9'><mark>reaches</mark></a> , 290 kilometres ( 180 mi ) West of Toronto and 106 kilometres ( 66 mi ) North of Detroit . 
Sarnia is located on the eastern shore of Lake Huron at its extreme southern point where it flow into the St. Clair River . Most of da surrounding area flat , and tdaelevation range from 169 metres ( 554 ft ) and 281 metres ( 922 ft ) above sea level . The soil mostly comprise clay . Despite this high percentage of clay , thdaoil remarkably rich fa cultivation . Prior to the Ice Age , glaciers covered most of the area , as can b seen not only by thedaistence of the daat Lakes themselves but also of alluvial sand deposits , terminal moraines , and rich oil reserves . The entire area was submerged and plant and animal matter formed many layers of sediment as they settled after the waters receded . Sarnia ain't no part of the Canadian Shield and is located just beyond its southernmost reach , 290 kilometres ( 180 mi ) West of Toronto and 106 kilometres ( 66 mi ) North of Detroit .