"If you define the total order of a set of time ranges as an ordering on their beginnings" What is the data type of the beginning of a range of time, if not a

"If you define the total order of a set of time ranges as an ordering on their beginnings" What is the data type of the beginning of a range of time, if not a point in time? I'm having trouble even defining ranges without points. I'd be interested to hear your suggestions in more detail. There's a temporal data LinkedIn group that you are welcome to join (I haven't been as active lately, but I'll try to get back into it). It would be a better forum to discuss matters like this.