Before the body was sent to the crematorium, shilling and Crump filled the casket with animal bones, meat, and a mannequin.
Object of the preposition: genius. The subject of the sentence is called a noun clause. It is a clause because it has its own subject and verb. It is also a dependent clause which cannot stand on its own because of the word that (a relative pronoun) at the beginning of the clause. A noun clause functions as a regular noun in a sentence.
Also that is not a sentence as it lacks a verb. It is a subject (The total amount) with a long prepositional phrase (specified in..) with a nested prepositional phrase (attached to...). I think you are looking for something closer to 'this', 'enclosed', or 'attached' depending on the context.