AMUSEMENT COMPANY OPEN OFFICES AT LAKEThe American Amusement company, which is planning to build a $500,000 Coney Island at Lake Wichita, will open an office for the construction foreman at the Lake Wichita pavilion next Monday or Tuesday, officials announced here Thursday.Actual construction work will be started by Dec. 1. The company expects to open its new park on May 1. Features of the park will include a giant toboggan slide, many rides,summer hotel accommodations,summer cottages, camp grounds,ballroom and water sports.