I'd put a comma after 'a century before'. The second point could be punctuated in different ways. The simplest would be one comma before 'and. You could also put 'above the stream bed' between commas, though many wouldn't.
Second text- no, don't put an 's' on other when it comes before a noun- when it is a pronoun, then it has a plural.
Third text- it's a comma splice, which is a common mistake among native speakers too.