Mont St Michel to Paris

already in Mont St Michel and do not have a car.

I am new to this and just wondering why it isn't faster to take a taxi to Pontorson, train from Pontorson to Rennes, and then train to Paris?

We will be spending the night at Mont St Michele and then we will be going to Paris so I am wanting to leave Mont St Michele fairly early in the morning to be in Paris in the late afternoon. Thanks for your help.

According to the DB timetables, whether you take a bus directly from Mont-St-Michel to Rennes or a train from Pontorson to Rennes, the first train to Paris that you can catch at Rennes departs at 11:05 and arrives in Paris at 13:25.